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Sustainability considerations for organic electronic products
Abstract
The development of organic electronic applications has reached a critical point. While markets, including the Internet of Things, transparent solar and flexible displays, gain momentum, organic light-emitting diode displays lead the way, with a current market size of over $25 billion, helping to create the infrastructure and ecosystem for other applications to follow. It is imperative to design built-in sustainability into the materials selection, processing and device architectures of all of these emerging applications, and to close the loop for a circular approach. In this Perspective, we evaluate the status of embedded carbon in organic electronics, as well as options for more sustainable materials and manufacturing, including engineered recycling solutions that can be applied within the product architecture and at the end of life. This emerging industry has a responsibility to ensure a 'cradle-to-cradle' approach. We highlight that ease of dismantling and recycling needs to closely relate to the product lifetime, and that regeneration should be facilitated in product design. Materials choices should consider the environmental effects of synthesis, processing and end-product recycling as well as performance.
... strain and exhibiting mechanical resilience while retaining strength throughout their operation [3][4][5]. Fibrous magnetic materials are particularly intriguing since they can generate mechanical motion without being tethered to an external power source [6][7][8][9]. ...
... To summarize, the negative environmental impact of materials used in soft electronics and robotics has to be tackled at the design level [4,5,71]. In line with this, we herein present a manufacturing process of spider silk composite fibers that employ only water-based solvents and ambient temperature. ...
Flexible magnetic materials have great potential for biomedical and soft robotics applications, but they need to be mechanically robust. An extraordinary material from a mechanical point of view is spider silk. Recently, methods for producing artificial spider silk fibers in a scalable and all-aqueous-based process have been developed. If endowed with magnetic properties, such biomimetic artificial spider silk fibers would be excellent candidates for making magnetic actuators. In this study, we introduce magnetic artificial spider silk fibers, comprising magnetite nanoparticles coated with meso-2,3-dimercaptosuccinic acid. The composite fibers can be produced in large quantities, employing an environmentally friendly wet-spinning process. The nanoparticles were found to be uniformly dispersed in the protein matrix even at high concentrations (up to 20% w/w magnetite), and the fibers were superparamagnetic at room temperature. This enabled external magnetic field control of fiber movement, rendering the material suitable for actuation applications. Notably, the fibers exhibited superior mechanical properties and actuation stresses compared to conventional fiber-based magnetic actuators. Moreover, the fibers developed herein could be used to create macroscopic systems with self-recovery shapes, underscoring their potential in soft robotics applications.
... Conjugated polymers receive widespread interest for a myriad of applications from energy technology to wearable electronics and bioelectronics (1)(2)(3)(4)(5). To become truly viable, organic electronics must have a minimal environmental footprint that necessitates green synthesis and production (6)(7)(8). Materials should be selected not only for their superior electrical properties, but also for their accessibility via synthetic routes with low environmental impact. Several metrics are used to judge the environmental impact of a material. ...
Conjugated polymers are widely studied for application areas ranging from energy technology to wearable electronics and bioelectronics. To develop a truly sustainable technology, environmentally benign synthesis is essential. Here, the open-flask synthesis of a multitude of conjugated polymers at room temperature by ambient direct arylation polymerization (ADAP) is demonstrated. The batch synthesis of over 100 grams of polymer in a green solvent and continuous droplet flow synthesis without any solid support is described. Polymers prepared by ADAP are characterized by improved structural order compared to materials prepared by other methods. Hence, organic electrochemical transistors (OECTs) feature beyond state-of-the-art electrical properties, i.e., an OECT hole mobility μ as high as 6 cm ² V ⁻¹ s ⁻¹ , a volumetric capacitance C * over 200 F cm ⁻³ , and thus a figure of merit [μ C * ] exceeding 1100 F cm ⁻¹ V ⁻¹ s ⁻¹ . Thus, ADAP paves the way for the benign and large-scale production of high-performance conjugated polymers.
... Additionally, Heliatek has explored AM to produce organic solar films, a flexible and lightweight alternative to traditional panels [40]. Their use of AM has demonstrated a 30% reduction in production costs while improving the efficiency of solar energy conversion for flexible and portable applications [41]. These case studies will illustrate the tangible benefits of AM in terms of cost reduction, improved production speed, and enhanced performance for both wind turbine blades and solar panels. ...
The advent of additive manufacturing, commonly known as 3D printing has opened new avenues for innovation in various industries, including the energy sector. This review focuses on the application of additive manufacturing in the energy sector and its determining parameters, stressing the new opportunities, and challenges the fourth industrial revolution (4IR) presents. The applications of additive manufacturing in producing on-demand components, spare parts, and optimized designs for improved energy efficiency are explored. Additive manufacturing's ability to reduce costs and time for energy machines and components to enhance efficiency will be crucial for renewable energy sources. A comprehensive analysis of previous studies was conducted to investigate the influence of additive manufacturing in various sectors. Findings from this review could facilitate an accelerated adoption of additive manufacturing in expanding the energy sector.
... The point-like light-emitting diode (LED) is the most efficient and long-lasting EL technology as of today 5 , while the organic LED (OLED) instead offers large-area emission from lightweight and flexible device architectures 6,7 . However, from a sustainability viewpoint, it is a drawback that current commercial LED and OLED devices are fabricated by energy-intensive thermal evaporation under vacuum, and that they comprise geopolitically problematic materials, such as iridium, platinum, and rare earths, which are cumbersome to mine and recycle [8][9][10] . ...
The attainment of white emission from a light-emitting electrochemical cell (LEC) is important, since it enables illumination and facile color conversion from devices that can be cost-efficient and sustainable. However, a drawback with current white LECs is that they either employ non-sustainable metals as an emitter constituent or are intrinsically efficiency limited by that the emitter only converts singlet excitons to photons. Organic compounds that emit by thermally activated delayed fluorescence (TADF) can address these issues since they can harvest all excitons for light emission while being metal free. Here, we report on the first white LEC based on solely metal-free TADF emitters, as accomplished through careful tuning of the energy-transfer processes and the electrochemically formed doping structure in the single-layer active material. The designed TADF-LEC emits angle-invariant white light (color rendering index = 88) with an external quantum efficiency of 2.1 % at a luminance of 350 cd/m².
... 6, 7 However, from a sustainability viewpoint, it is a drawback that current commercial LED and OLED devices are fabricated by energy-intensive thermal evaporation under vacuum, and that they comprise geopolitically problematic materials, such as iridium, platinum and rare earths, which are cumbersome to mine and recycle. [8][9][10] The light-emitting electrochemical cell (LEC) is a less investigated and developed EL technology that is similar in appearance to the OLED, but which is distinguished by the existence of mobile ions in its active material. 11 These mobile ions redistribute during the initial LEC operation for the formation of electric double layers (EDLs) at the electrode interfaces and for the in-situ establishment of a p-n junction doping structure by electrochemical doping. ...
The attainment of broadband white emission from a light-emitting electrochemical cell (LEC) is important, since white light enables illumination and facile color conversion and because LEC devices can be cost-efficient, conformable and sustainable. However, a drawback with current white-emitting LECs is that they either employ non-sustainable metals as a critical emitter constituent or are intrinsically efficiency limited by that the emitter only converts singlet (and not triplet) excitons to photons. Organic compounds that emit by the process of thermally activated delayed fluorescence (TADF) can address these issues since they can harvest all the electrically generated excitons for light emission while being metal free. Here, we report on the first white LEC that utilizes solely metal-free TADF compounds for the emitting species. This was accomplished through systematic design, investigation and tuning of the energy-transfer processes and the electrochemically formed doping structure within the metal-free LEC active material, which comprises two color-complementary blue and orange TADF emitters, a blend host and an ionic-liquid electrolyte. The tuned TADF-LEC emits white light with a high color rendering index of 88 and CIE coordinates of (0.36, 0.38), and this broadband emission, which can be delivered at an external quantum efficiency of 2.11% and a luminance of 350 cd/m ² , is demonstrated to be highly invariant to both viewing angle, operational time and current density.
... Organic devices can be fabricated by low-energy and resource-efficient solution-based methods using non-toxic materials, which is key to reducing the carbon and waste footprint of optoelectronic products. [1][2][3] Among others, solution-processed light-emitting diodes (OLEDs), 4 wavelength and oxygen sensors, 5,6 photoluminescent tags (PLTs), 7 photovoltaics (OPVs), 8 and electrochemical transistors (OECTs) 9 have been demonstrated. Light-emitting electrochemical cells (LECs) are particularly appealing in this context, as their entire device structure, i.e. the single active-material layer and the two air-stable electrodes, can be fabricated under ambient conditions 10,11 using non-toxic solvents. ...
Light-emitting electrochemical cells (LECs) are promising candidates for fully solution-processed lighting applications because they can comprise a single active-material layer and air-stable electrodes. While their performance is often claimed to be independent of the electrode material selection due to the in-situ formation of electric double layers (EDLs), we demonstrate conceptually and experimentally that this understanding needs to be modified. Specifically, the exciton generation zone is observed to be affected by the electrode work function. We rationalize this finding by proposing that the ion concentration in the injection-facilitating EDLs depends on the offset between the electrode work function and the respective semiconductor orbital, which in turn influences the number of ions available for electrochemical doping and hence shifts the exciton generation zone. Further, we investigate the effects of the electrode selection on exciton losses to surface plasmon polaritons and discuss the impact of cavity effects on the exciton density. We conclude by showing that the measured electrode-dependent LEC luminance transients can be replicated by an optical model that considers these electrode-dependent effects to calculate the attained light outcoupling of the LEC stack. As such, our findings provide rational design criteria considering the electrode materials, the active-material thickness, and its composition in concert to achieve optimum LEC performance.
... Salient features of photoactive organic molecules include potential for lowercost, green synthesis and processing, as well as simpler and nimbler manufacturing compared to their inorganic counterparts. 1,2 This article reports on the synthesis, optical spectroscopic properties, and laser and bioimaging potentials of a group of organic molecules 2,4,6-triphenylpyrylium tetrachloroferrate and its derivatives. ...
... These advances often approach or even surpass the quality and efficiency of pre-existing non-organic technologies at usually reduced costs and environmental impact. [27][28][29][30] OE have gained renewed attention as a promising field to promote sustainable energy production, [31][32][33] biomimetics, 34,35 environmental sensing devices and health monitoring, 36,37 and secure digitalization efforts like the Internet of Things (IoT) 38,39 all while being less dependent on rare earth metals. ...
Organic electronics (OE) such as organic light-emitting diodes or organic solar cells represent an important and innovative research area to achieve global goals like environmentally friendly energy production. To accelerate OE material discovery, various computational methods are employed. For the initial generation of structures, a molecular cluster approach is employed. Here, we present a semi-automated workflow for the generation of monolayers and aggregates using the GFNn-xTB methods and composite density functional theory (DFT-3c). Furthermore, we present the novel D11A8MERO dye interaction energy benchmark with high-level coupled cluster reference interaction energies for the assessment of efficient quantum chemical and force-field methods. GFN2-xTB performs similar to low-cost DFT, reaching DFT/mGGA accuracy at two orders of magnitude lower computational cost. As an example application, we investigate the influence of the dye aggregate size on the optical and electrical properties and show that at least four molecules in a cluster model are needed for a qualitatively reasonable description.
... However, the stability of solar cells is a key issue to be addressed. [7] Research shows that material composition, active layer morphology, carrier transport layer optimization and processing methods have a significant impact on the efficiency and stability of solar cells. There are many factors related to the stability of OSCs and PSCs, including the intrinsic stability, photothermalinduced degradation, oxygen and water in the air, mechanical instability, etc. [8] Scientists have been working on various aspects to improve the performance and stability of solar cells, but research on the mechanism and physical theory of device stability is still lacking. ...
The emerging photovoltaic (PV) technologies, such as organic and perovskite PVs, have the characteristics of complex compositions and processing, resulting in a large multidimensional parameter space for the development and optimization of the technologies. Traditional manual methods are time‐consuming and labor‐intensive in screening and optimizing material properties. Materials genome engineering (MGE) advances an innovative approach that combines efficient experimentation, big database and artificial intelligence (AI) algorithms to accelerate materials research and development. High‐throughput (HT) research platforms perform multidimensional experimental tasks rapidly, providing a large amount of reliable and consistent data for the creation of materials databases. Therefore, the development of novel experimental methods combining HT and AI can accelerate materials design and application, which is beneficial for establishing material‐processing‐property relationships and overcoming bottlenecks in the development of emerging PV technologies. This review introduces the key technologies involved in MGE and overviews the accelerating role of MGE in the field of organic and perovskite PVs.
... However, this will require electronic devices that can interface with various parts of the human body and collect signals with sufficient quality, resolution, and stability [5,6]. In the foreseeable time, electronic products are expected to play an even more critical role in healthcare, medicine, biological research, and human-machine interfaces [7][8][9]. The compatible and tight integration of electronic devices with the human body can be achieved by improving biocompatibility [10], enhancing compatibility, and inhibiting intrusive reactions [11,12]. ...
Future electronics will play a more critical role in people’s lives, as reflected in the realization of advanced human–machine interfaces, disease detection, medical treatment, and health monitoring. The current electronic products are rigid, non-degradable, and cannot repair themselves. Meanwhile, the human body is soft, dynamic, stretchable, degradable, and self-healing. Consequently, it is valuable to develop new electronic materials with skin-like properties that include stretchability, inhibition of invasive reactions, self-healing, long-term durability, and biodegradability. These demands have driven the development of a new generation of electronic materials with high-electrical performance and skin-like properties, among which e-polymers are increasingly being more extensively investigated. This review focuses on recent advances in synthesizing e-polymers and their applications in biointerfaces and organisms. Discussions include the synthesis and properties of e-polymers, the interrelationships between engineered material structures and human interfaces, and the application of implantable and wearable systems for sensors and energy harvesters. The final section summarizes the challenges and future opportunities in the evolving materials and biomedical research field.
... Such a high thermal treatment can be detrimental for large-scale production, both for energy consumption and viability of flexible substrates used in roll-to-roll industrial manufacturing. 24 In the case of the nanoprecipitation methodology, the use of two miscible phases leads to rapid nanoparticle formation upon mixing. Its mechanism can be decomposed in two steps (nucleation and growth of the nuclei), which occur on a very short timescale of a few microseconds, leaving a short time for the active material to organize (Figure 1). 25 Even though the mechanism is fast, interactions of material/medium interfacial energies influence the main nanoparticle morphology. ...
Organic photovoltaics is a promising technology, giving access to lightweight, semitransparent and flexible devices with a low energy pay-back time. Recently, impressive improvements were achieved (up to 19% power conversion efficiencies – PCE – for a single-junction) thanks to the development of novel donor and acceptor semi-conducting materials for the active layer, which present complementary absorptions. These solar cells can be processed at a large-scale using printing and roll-to-roll industrial techniques. However, by considering environmental aspects, one limitation may come from the active layer deposition that uses organic (harmful) solvents. To address this issue, water-based inks can be prepared, in which
the active materials are dispersed as nanoparticles. However, in order to form a homogeneous thin active layer film from nanoparticle assemblies, a thermal treatment is mandatory to ensure nanoparticle sintering. We show how the ink preparation technique is a key parameter to promote the formation of ‘soft’ nanoparticles (containing less crystallised materials) instead of ‘hard’ nanoparticles, allowing a sintering at an industrial compatible temperature (130°C instead of 200°C, respectively). Design of amorphous nanoparticles not only significantly reduced the processing temperatures, but also allowed to achieve high efficiencies for water-based solar cells up to 10% PCE.
... Qxs can be readily prepared through simple condensation reactions, enabling convenient experimental studies and cost-effective bulk production [5]. The availability of inexpensive and accessible starting materials further enhances the practicality and commercial viability of Qxs for charge transport applications [6][7][8][9][10]. Figure 1 shows a few Qx scaffolds used in development of Qx derivatives. ...
This review article provides a comprehensive overview of recent advancements in electron transport materials derived from quinoxaline, along with their applications in various electronic devices. We focus on their utilization in organic solar cells (OSCs), dye-sensitized solar cells (DSSCs), organic field-effect transistors (OFETs), organic-light emitting diodes (OLEDs) and other organic electronic technologies. Notably, the potential of quinoxaline derivatives as non-fullerene acceptors in OSCs, auxiliary acceptors and bridging materials in DSSCs, and n-type semiconductors in transistor devices is discussed in detail. Additionally, their significance as thermally activated delayed fluorescence emitters and chromophores for OLEDs, sensors and electrochromic devices is explored. The review emphasizes the remarkable characteristics and versatility of quinoxaline derivatives in electron transport applications. Furthermore, ongoing research efforts aimed at enhancing their performance and addressing key challenges in various applications are presented.
Solution‐processable organic solar cells (OSCs) represent a promising renewable photovoltaic technology with significant potential for eco‐compatible production. While high power conversion efficiencies (PCEs) have been achieved in OSCs, scaling this technology for high‐throughput manufacturing remains challenging. Key reason lies in the lack of efficient control strategies for the complex and long‐duration morphology evolution during high‐speed coating process with ecofriendly solvents. Here, a donor‐priority rapid aggregation process (DP‐RAP) scheme is proposed to solve this issue by adjusting the aggregation kinetics of donor and acceptor components. DP‐RAP enables blends with a nanoscale fiber network structure and favorable crystallinity, which contributes to balanced carrier transport and reduced recombination losses. As a result, the PCE is improved from 14.3% (reference) to 17.4% (DP‐RAP) for ultra‐high speed coated PM6:BTP‐eC9 devices in atmosphere, which is one of the highest values for non‐halogenated solvent‐processed solar cells at coating speeds of 500 mm s⁻¹. Moreover, the DP‐RAP based devices remain a stable PCE of approximately 17.4% across a broad range of coating speeds (20–500 mm s⁻¹), illustrating its tolerance to the varied manufacturing conditions. This work highlights a promising avenue for the high‐speed, ecofriendly production of efficient OSCs, pushing the boundaries of practical manufacturing in renewable energy technologies.
Organic semiconductors possessing both green-solvent processability and superior efficiency are highly desirable for green electronics. A simple but effective strategy to improve the solubility of high-performance organic semiconductors in nonhalogenated...
Temperature sensors play a pivotal role in modern electronics, finding use across a broad spectrum of applications. Nonetheless, traditional manufacturing methods for these devices consume substantial energy and materials, and their widespread utilization often contributes to substantial electronic waste, presenting significant environmental concerns. In this research, recyclable printed thermocouple temperature sensors are developed that emphasize both cost‐efficiency and ecological responsibility. The sensors utilize readily available fillers (i.e., nickel flakes and carbon black powders), paving the way for scalable production. By incorporating re‐dissolvable polymers as binders, the end‐of‐life sensors can be easily disassembled, eliminating the need for harsh treatment or hazardous chemicals. The use of ferromagnetic nickel flakes enhances the straightforward separation of different filler components, streamlining the recycling workflow. Importantly, the gentle recycling conditions preserve the functional fillers, preventing degradation or oxidation and thus enabling the reprocessed sensors to retain their original performance. In addition, the sensors boast high mechanical flexibility, making them suitable for seamless integration into various practical scenarios. All these innovations not only reduce economic costs but also align with the goals of sustainable development, demonstrating a promising pathway for the future of temperature sensing technology.
There is a pressing need to reduce electronic waste, which along with government edicts and national time‐bound policy directives are shaping the drive toward circular economy solutions in electronics. However, there is no industrially standardized approach for fabricating high‐throughput recyclable and reusable electronic assemblies. Herein, we present the functionalization of steel over large areas with low‐cost insulative intermediate layers as Printed Circuit Boards (PCBs), enabling an electronics circular economy. Roll‐to‐roll‐friendly reusable steel substrates are coated using Sol–gel‐based low‐roughness insulative layers, with conductive tracks and solder pads additively manufactured with direct‐write printing. To demonstrate how degradable 3D scaffolds could enable wireless applications, RF components, and wi‐fi nodes are demonstrated with 3D‐printed antennas showing the feasibility of broadband Internet of Things applications up to 6 GHz. At their end‐of‐life, the steel‐based PCBs are sonicated in non‐hazardous solvents allowing for the rapid recovery of components and precious metals. The environmental benefits of our approach are discussed using Life Cycle Assessments (LCA) and a comparative LCA between these scenarios has been undertaken. Consideration of the final product cost is given and potential business models to enter the electronics market are identified.
Conjugated polymers with simple chemical structures are essential for the commercialization of organic solar cells (OSCs). However, a simplicity-performance dilemma arises, as current design principles often result in an inverse...
Post‐Li battery technologies are becoming increasingly important. The diverse range of electrically powered devices requires a diversification of electrochemical energy storage technologies. Organic electrode materials are of particular importance for alternative batteries, not only because of the natural abundance of their constituting elements and low toxicity, but also because of the operating principle of their redox reactions and their compatibility with many types of battery chemistries, including multivalent metal and anionic batteries. All‐organic batteries are a still a “young” field of research but offer promising opportunities in terms of mechanical and processing properties. In the development of batteries using organic electrode materials the understanding of their redox mechanisms, of the different cell types and the correct interpretation of data is of utmost importance. This comprehensive review offers insight into the working principle of organic‐based batteries, into material design considerations, structure‐property relations, highlighting the importance of standardized terminology, and into the characterization of newly developed organic electrode materials in battery cells, distinguishing between half‐cells and full‐cells.
Conjugated polymers are promising semiconducting materials for applications in organic electronic devices such as organic light‐emitting diodes (OLEDs). Recent advances in direct arylation polycondensation have enabled the synthesis of defect‐free polymers in the main chain; however, terminal groups have not been fully investigated. This research focuses on the synthesis of polymers with controlled terminal groups and the evaluation of their effects on photophysical and OLED properties. Investigation of the monomer feed ratio and terminal treatment methods allows the synthesis of three polymers with different terminal groups. The terminal groups affect the photoluminescence quantum yield in the thin‐film state and the external quantum efficiency in OLEDs. These findings indicate that a small percentage of terminal groups in the polymer material has a significant impact on the device properties.
Bulk heterojunction (BHJ) organic solar cells can offer a range of specific advantages, making them suitable for potential integration into a wide variety of applications. This circumstance is driving an ever increasing attention to the environmental profile of this technology throughout its entire life cycle. Consequently, alternative materials and processes with a reduced environmental impact attract interest from researchers focused on developing a new generation of eco‐designed devices. In this context, biomaterials represent an emerging class of sustainable alternatives suitable for use as active and passive components. For instance, some biomaterials can be successfully employed as alternative substrates for flexible solar cells, achieving performances comparable to those of state‐of‐the‐art devices built on plastic. In this work, the preparation of organic solar cells is presented, integrating a water‐processed sodium alginate film as a substrate, with the dual purpose of optimizing the efficiency of the resulting devices and investigating their stability. Specifically, PM6:Y6‐based cells built on SA substrates exhibit a power conversion efficiency that exceeds 10% while showing excellent thermal and mechanical stabilities. These results demonstrate the potential of sodium alginate as a viable candidate for the realization of efficient and stable eco‐designed devices.
Semitransparent organic photovoltaics (ST-OPVs), as a novel green energy acquisition technology, are one of the most promising applications in organic photovoltaics. Because of its intrinsic transmittance originated from adjustable absorption, light weight and flexibility, ST-OPVs, compared with other inorganic photovoltaics, show unique potential in wearable devices, self-powered greenhouse roofs and building integrated photovoltaics. To further promote the practicality and industrialization of ST-OPVs, the light utilization efficiency is still the focus of research. Hence, the recent progress of ST-OPVs is reviewed from the theoretical models, transparent top electrodes, the optical modification and selection of active layer materials. We hope that this paper will provide valuable guidelines for the ST-OPV research.
Light-emitting electrochemical cells (LECs) are promising candidates for fully solution-processed lighting applications because they can comprise a single active-material layer and air-stable electrodes. While their performance is often claimed to be independent of the electrode material selection due to the in situ formation of electric double layers (EDLs), we demonstrate conceptually and experimentally that this understanding needs to be modified. Specifically, the exciton generation zone is observed to be affected by the electrode work function. We rationalize this finding by proposing that the ion concentration in the injection-facilitating EDLs depends on the offset between the electrode work function and the respective semiconductor orbital, which in turn influences the number of ions available for electrochemical doping and hence shifts the exciton generation zone. Further, we investigate the effects of the electrode selection on exciton losses to surface plasmon polaritons and discuss the impact of cavity effects on the exciton density. We conclude by showing that we can replicate the measured luminance transients by an optical model which considers these electrode-dependent effects. As such, our findings provide rational design criteria considering the electrode materials, the active-material thickness, and its composition in concert to achieve optimum LEC performance.
Pure organic, easily processed, and flexible X-ray scintillating films based on TADF materials for high-resolution imaging with over 20 line pairs per mm.
Significant advancements in power conversion efficiency have been achieved in organic solar cells with small molecule acceptors. However, stability remains a primary challenge, impeding their widespread adoption in renewable energy applications. This review summarizes the degradation of different layers within the device structure in organic solar cells under varying conditions, including light, heat, moisture, and oxygen. For the photoactive layers, the chemical degradation pathways of polymer donors and small molecule acceptors are examined in detail, alongside the morphological stability of the bulk heterojunction structure, which plays a crucial role in device performance. The degradation mechanisms of commonly used anode and cathode interlayers and electrodes are addressed, as these layers significantly influence overall device efficiency and stability. Mitigation methods for the identified degradation mechanisms are provided in each section to offer practical insights for improving device longevity. Finally, an outlook presents the remaining challenges in achieving long‐term stability, emphasizing research directions that require further investigation to enhance the reliability and performance of organic solar cells in real‐world applications.
Over the past decades, organic optoelectronic devices have shown broad application prospects. Due to the solubility property of organic materials, the use of toxic solvent obstacles the device fabrication processing...
Organic electroactive materials, particularly semiconducting polymers, are at the forefront of emerging organic electronics. Among the plethora of unique features, the possibility to formulate inks out of these materials is particularly promising for the large‐scale manufacturing of electronics at lower cost on a variety of soft substrates. While solution deposition of semiconducting materials is promising for developing printed electronics, the environmental footprint of the materials and related devices needs to be considered to achieve sustainable manufacturing. Towards the development of greener printed electronics, this work investigates the utilization of a non‐toxic, environmentally‐friendly solvent, namely branched polyethylene (BPE), to formulate semiconducting inks. Focusing on a diketopyrrolopyrrole‐based (DPP) semiconducting polymer, shellac as dielectric, and BPE as the solvent, solutions were prepared in different concentrations and their rheological properties were characterized. Then, printing on polyethylene terephthalate (PET) substrates using two different techniques was performed to fabricate organic field‐effect transistors (OFETs). Both printing techniques yielded OFETs with good performance and device characteristics, averaging approximately 10 ⁻² and 10 ⁻⁴ cm ² V ⁻¹ s ⁻¹ , respectively, for slot‐die coating and direct‐ink writing deposition. Notably, despite some difference in threshold voltages, OFETs produced via slot‐die coating and direct‐ink writing showed comparable charge mobilities to previously reported OFETs prepared from similar materials, particularly those prepared on silicon dioxide wafers. Overall, this work confirms the suitability of BPE to formulate semiconducting inks to develop printed electronics in a greener manner. The printing methodology developed in this work also open new avenues for the design of functional printed electronics and related technologies.
In this study, innovative nanoscale devices are developed to investigate the charge transport in organic semiconductor nanoparticles. Using different steps of lithography techniques and dielectrophoresis, planar organic nano‐junctions are fabricated from which hole mobilities are extracted in a space charge‐limited current regime. Subsequently, these devices are used to investigate the impact of the composition and morphology of organic semiconductor nanoparticles on the charge mobilities. Pure donor nanoparticles and composite donor:acceptor nanoparticles with different donor compositions in their shell are inserted in the nanogap electrode to form the nano‐junctions. The results highlight that the hole mobilities in the composite nanoparticles decrease by two‐fold compared to pure donor nanoparticles. However, no significant change between the two kinds of composite nanoparticle morphologies is observed, indicating that conduction pathways for the holes are as efficient for donor proportion in the shell from 40% to 60%. Organic photovoltaic (OPV) devices are fabricated from water‐based colloidal inks containing the two composite nanoparticles (P3HT:eh‐IDTBR and P3HT:o‐IDTBR) and no significant change in the performances is observed in accordance with the mobility results. Through this study, the performance of OPV devices have been succesfully correlated to the transport properties of nanoparticles having different morphology via innovative nanoscale devices.
Development of organic field-effect transistors (OFETs) that simultaneously exhibit high-performance and high-stability is critical for complementary integrated circuits and other applications based on organic semiconductors. While progress has been made...
Organic X‐ray sensors are a promising new class of detectors with the potential to revolutionize medical imaging, security screening, and other applications. However, the development of high‐performance organic X‐ray sensors is challenged by low sensitivity. This paper reports on the development of nine X‐ray sensors based on new organic materials. It is demonstrated that the incorporation of bromine atoms into the sidechains of carbazolyl‐containing organic molecules significantly enhances their X‐ray sensitivity. This research suggests that incorporating a variety of high‐atomic‐number chemical elements into well‐established organic semiconductors is a promising strategy for designing efficient X‐ray sensor materials.
While organic semiconductors hold significant promise for the development of flexible, lightweight electronic devices such as organic thin-film transistors (OTFTs), photodetectors, and gas sensors, their widespread application is often limited by intrinsic challenges. In this article, we first review these challenges in organic electronics, including low charge carrier mobility, susceptibility to environmental degradation, difficulties in achieving uniform film morphology and crystallinity, as well as issues related to poor interface quality, scalability, and reproducibility that further hinder their commercial viability. Next, we focus on reviewing the hybrid system comprising an organic semiconductor and polystyrene (PS) to address these challenges. By examining the interactions of PS as a polymer additive with several benchmark semiconductors such as pentacene, rubrene, 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS pentacene), 2,8-difluoro-5,11-bis(triethylsilylethynyl) anthradithiophene (diF-TES-ADT), and 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C8-BTBT), we showcase the versatility of PS in enhancing the crystallization, thin film morphology, phase segregation, and electrical performance of organic semiconductor devices. This review aims to highlight the potential of an organic semiconductor/PS hybrid system to overcome key challenges in organic electronics, thereby paving the way for the broader adoption of organic semiconductors in next-generation electronic devices.
Pursuing power conversion efficiency (PCE) is the priority of developing organic solar cells (OSCs) based on low‐cost completely non‐fused ring acceptors. Herein, a donor/acceptor re‐intermixing strategy to enhance the photon capturing process, based on a previously established well‐stratified active layer morphology is reported. By adding 20 wt% PTQ10 (polymer donor) into the acceptor's precursor, the device PCE is increased to 16.03% from 15.11% of the D18/A4T‐16 control system, which is attributed to the additional charge generation interface and suppressed bimolecular recombination. On the contrary, using the equal ratio of PM6 leads to significant efficiency loss, indicating the importance of considering vertical distribution from the perspective of thermodynamics. Moreover, a cutting‐edge level of 17.21% efficiency for completely non‐fused ring acceptor systems is realized by altering the active layer to PBQx‐TF/TBT‐26 and PTQ11, via the identical processing strategy. This work thus presents attractive device engineering and solar cell performance, as well as in‐depth vertical morphology understanding.
The synthesis and characterization of four ethylene-bridged bisisoindigo (NCCN and NNNN)-based conjugated polymers are reported. In these polymers, 2,2'-bithiophene or (E)-1,2-di(thiophen-2-yl)ethene (DTE) is used as the electron donor. Compared to...
Carbon-based nanomaterials (CBNMs), including graphene, carbon nanotubes (CNTs), fullerenes, and nanodiamonds, are poised to revolutionize sustainable environmental applications. Graphene's unparalleled mechanical strength, electrical conductivity, and thermal properties make it crucial for water purification and energy storage. CNTs, with their exceptional tensile strength, conductivity, and chemical stability, are vital in pollution control and energy conversion. Fullerenes, noted for their electronic properties and high reactivity, excel in environmental remediation. Nanodiamonds offer exceptional hardness, thermal conductivity, and biocompatibility, promising applications from soil remediation to biomedical engineering. However, challenges such as toxicity, cost, and scalability must be addressed. Future research should focus on overcoming these hurdles and fostering interdisciplinary collaboration to fully harness CBNMs for sustainable solutions.
Photocatalyst systems combining donor polymers with acceptor molecules have shown the highest evolution rates for sacrificial hydrogen production from water for organic systems to date. Here, new donor molecules have...
The development of the Internet of Things (IoT) indicates that humankind has entered a new intelligent era of the “Internet of Everything”. Thanks to the characteristics of low‐cost, diverse structure, and high energy conversion efficiency, the self‐powered sensing systems, which are based on the Triboelectric Nanogenerator (TENG), demonstrate great potential in the field of IoT. In order to solve the challenges of TENG in sensing signal processing, such as signal noise and nonlinear relations, Machine Learning (ML), which is an efficient and mature data processing tool, is widely applied for efficiently processing the large and complex output signal data generated by TENG intelligent sensing system. This review summarizes and analyzes the adaptation of different algorithms in TENG and their advantages and disadvantages at the beginning, which provides a reference for the selection of algorithms for TENG. More importantly, the application of TENG is introduced in multiple scenarios, including health monitoring, fault detection, and human‐computer interaction. Finally, the limitations and development trend of the integration of TENG and ML are proposed by classification to promote the future development of the intelligent IoT era.
Debondable pressure‐sensitive adhesives (PSAs) promise access to recyclability in microelectronics in the transition toward a circular economy. Two PSAs were synthesized from a tetravalent thiol star‐polyester forming thiol‐catechol‐connectivities (TCC) with either the biorelated DiDopa‐bisquinone (BY*Q) or the fossil‐based bisquinone A (BQA). The PSAs enable debonding by oxidation of TCC‐catechols to quinones. The extent of debonding efficiency depends on the interaction modes, which are determined by the chemical structure differences of both TCC‐motifs. BY*Q‐TCC‐PSA debonds with exceptional loss of 99 % of its approx. 2 MPa shear strength in glass‐on‐glass junctions. For BQA‐TCC‐PSA, a debonding efficiency of only approx. 60 % was found, irrespective of its initial shear strength, which could be tuned up to approx. 7 MPa. The efficiency of debonding for BY*Q‐TCC‐PSA after TCC‐oxidation is linked to the loss of synergistic interactions without strongly affecting the bulk glue properties, outperforming the purely catechol‐based BQA‐analogue.
Debondable pressure‐sensitive adhesives (PSAs) promise access to recyclability in microelectronics in the transition toward a circular economy. Two PSAs were synthesized from a tetravalent thiol star‐polyester forming thiol‐catechol‐connectivities (TCC) with either biorelated DiDopa‐bisquinone (BY*Q) or fossil‐based bisquinone A (BQA). The PSAs enable debonding by oxidation of TCC‐catechols to quinones. The extent of debonding efficiency depends on the interaction modes, which are determined by the chemical structure differences of both TCC‐motifs. BY*Q‐TCC‐PSA debonds with exceptional loss of 99% of its approx. 2 MPa shear strength. For BQA‐TCC‐PSA, a debonding efficiency of only approx. 60% was found, irrespective of its initial shear strength, which could be tuned up to approx. 7 MPa. The efficiency of debonding for BY*Q‐TCC‐PSA after TCC‐oxidation is linked to the loss of synergistic interactions without strongly affecting the bulk glue properties, outperforming the purely catechol‐based BQA‐analogue.
This review provides a historic overview of the photodegradation mechanisms of photoactive materials in organic solar cells, shedding light on the role of photochemical photodegradation pathways to pave the way for stable organic photovoltaics.
Through direct arylation polymerization, a series of mixed ion-electron conducting polymers with a low synthetic complexity index is synthesized. A thieno[3,2-b]thiophene monomer with oligoether side chains is used in direct arylation polymerization together with a wide range of aryl bromides with varying electronic character from electron-donating thiophene to electron-accepting benzothiadiazole. The obtained polymers are less synthetically complex than other mixed ion–electron conducting polymers due to higher yield, fewer synthetic steps and less toxic reagents. Organic electrochemical transistors (OECTs) based on a newly synthesized copolymer comprising thieno[3,2-b]thiophene with oligoether side chains and bithiophene exhibit excellent device performance. A high charge-carrier mobility of up to μ = 1.8 cm² V⁻¹ s⁻¹ was observed, obtained by dividing the figure of merit [μC*] from OECT measurements by the volumetric capacitance C* from electrochemical impedance spectroscopy, which reached a value of more than 215 F cm⁻³.
Donor–acceptor (D–A)‐conjugated polymers have achieved promising performance metrics in numerous optoelectronic applications that continue to motivate studying structure–property relationships and discovering new materials. Here, the materials toolbox is expanded by synthesizing D–A copolymers where 1,4‐dihydropyrrolo[3,2‐ b ]pyrrole (DHPP) is directly incorporated into the main chain of D–A copolymers for the first time via direct heteroarylation polymerization. Notably, the synthetic complexity of DHPP‐containing polymers coupled with thieno[3,2‐ b ]pyrrole‐4,6‐dione (TPD) or 3,6‐bis(2‐thienyl)‐2,5‐dihydropyrrolo[3,4‐ c ]pyrrole‐1,4‐dione (Th 2 DPP) comonomers is calculated to be lower compared to many common conjugated polymers synthesized via direct arylation. The electron‐rich nature of DHPPs when coupled with TPD or DPP enables optoelectronic properties to be manipulated, evident by measuring distinctly different absorbance and redox properties. Additionally, these D–A copolymers demonstrate their potential in organic electronic applications, such as electrochromics and organic photovoltaics. The reported DHPP‐ alt ‐Th 2 DPP copolymer is the first DHPP‐based colored‐to‐transmissive electrochrome and achieves power conversion efficiencies of ~2.5% when incorporated into bulk heterojunction solar cells. Overall, the synthetic accessibility of DHPP monomers and their propensity to participate in robust polymerizations highlights the value of establishing structure–property relationships of an underutilized scaffold. These fundamental attributes serve to inform and advance efforts in the development of DHPP‐containing copolymers for various applications.
Organic thin-film transistors (OTFTs) have shown great potential as chemical and biological sensors for applications in environmental monitoring and diagnostics with high sensitivities and part-per-billion molar concentration limits of detection....
n‐Type organic electrochemical transistors (OECTs) are fundamental building blocks of biosensors and complementary circuits along with p‐type. Yet, their development has been lagging behind their p‐type counterparts since first emergence in 2016. The key component of an OECT is the channel material, which is an organic mixed ionic‐electronic conductor (OMIEC), that dictates the function and performance of the OECT via interactions with electrolyte ions. OMIECs of OECTs are benchmarked by the product of charge‐carrier mobility (μ) and volumetric capacitance (C*), μC*. Significant progress is made for the development of novel n‐type OMIECs, with best μC* now reaching 180 F cm⁻¹ V⁻¹ s⁻¹. This review elucidates such material development progress of n‐type OMIECs with emphases on the underlying molecular design strategies and structure‐property relationships. Furthermore, the operational stability of channel materials and the applications of n‐type OECTs are also discussed to offer readers a comprehensive view of the field. Finally, current limitations are discussed along with outlook.
The fine-tuning of molecular aggregation and the optimization of blend microstructure through effective molecular design strategies to simultaneously achieve high device efficiency and stability in all-polymer solar cells (all-PSCs) remains...
The advancement of semiconducting polymers stands as a pivotal milestone in the quest to realize wearable electronics. Nonetheless, endowing semiconductor polymers with stretchability without compromising their carrier mobility remains a formidable challenge. This study proposes a “pre‐endcapping” strategy for synthesizing hyperbranched semiconducting polymers (HBSPs), aiming to achieve the balance between carrier mobility and stretchability for organic electronics. The findings unveil that the aggregates formed by the endcapped hyperbranched network structure not only ensure efficient charge transport but also demonstrate superior tensile resistance. In comparison to linear conjugated polymers, HBSPs exhibit substantially larger crack onset strains and notably diminished tensile moduli. It is evident that the HBSPs surpass their linear counterparts in terms of both their semiconducting and mechanical properties. Among HBSPs, HBSP‐72h‐2.5 stands out as the preeminent candidate within the field of inherently stretchable semiconducting polymers, maintaining 93% of its initial mobility even when subjected to 100% strain (1.41 ± 0.206 cm² V⁻¹ s⁻¹). Furthermore, thin film devices of HBSP‐72h‐2.5 remain stable after undergoing repeated stretching and releasing cycles. Notably, the mobilities are independent of the stretching directions, showing isotropic charge transport behavior. The preliminary study makes this “pre‐endcapping” strategy a potential candidate for the future design of organic materials for flexible electronic devices.
The present study compares conventional printed circuit boards (having glass-fibre and epoxy substrates and etched copper circuits) with paper-based printed electronics (offering flexible, bio-based, and biodegradable substrates with circuit design printed using silver-based inks) and assesses the relevance of e-waste recycling to the latter's sustainability. Therefore, a comparative life cycle assessment between these two options has been undertaken and the global warming impacts were calculated.
The impact assessment results underscore that printed electronics offer a consistent sustainability advantage over printed circuit boards only through recycling of silver in the former at the end-of-life. Hence, design-for-recycling and recycling as e-waste are crucial to the sustainability of the current generation of printed electronics. Other foreseen waste treatment options for paper-based printed electronics, such as composting, and paper recycling, are likely to limit the sustainability advantage of printed electronics to circuits with small conductive areas.
Electronic devices are irrevocably integrated into our lives. Yet, their limited lifetime and often improvident disposal demands sustainable concepts to realize a green electronic future. Research must shift its focus on substituting nondegradable and difficult-to-recycle materials to allow either biodegradation or facile recycling of electronic devices. Here, we demonstrate a concept for growth and processing of fungal mycelium skins as biodegradable substrate material for sustainable electronics. The skins allow common electronic processing techniques including physical vapor deposition and laser patterning for electronic traces with conductivities as high as 9.75 ± 1.44 × 10 ⁴ S cm ⁻¹ . The conformal and flexible electronic mycelium skins withstand more than 2000 bending cycles and can be folded several times with only moderate resistance increase. We demonstrate mycelium batteries with capacities as high as ~3.8 mAh cm ⁻² used to power autonomous sensing devices including a Bluetooth module and humidity and proximity sensor.
The small specific entropy of mixing of high molecular weight polymers implies that most blends of dissimilar polymers are immiscible with poor physical properties. Historically, a wide range of compatibilization strategies have been pursued, including the addition of copolymers or emulsifiers or installing complementary reactive groups that can promote the in situ formation of block or graft copolymers during blending operations. Typically, such reactive blending exploits reversible or irreversible covalent or hydrogen bonds to produce the desired copolymer, but there are other options. Here, we argue that ionic bonds and electrostatic correlations represent an underutilized tool for polymer compatibilization and in tailoring materials for applications ranging from sustainable polymer alloys to organic electronics and solid polymer electrolytes. The theoretical basis for ionic compatibilization is surveyed and placed in the context of existing experimental literature and emerging classes of functional polymer materials. We conclude with a perspective on how electrostatic interactions might be exploited in plastic waste upcycling.
Perovskite photovoltaics are gaining increasing common ground to partner with or compete with silicon photovoltaics to reduce cost of solar energy. However, a cost-effective waste management for toxic lead (Pb), which might determine the fate of this technology, has not been developed yet. Here, we report an end-of-life material management for perovskite solar modules to recycle toxic lead and valuable transparent conductors to protect the environment and create dramatic economic benefits from recycled materials. Lead is separated from decommissioned modules by weakly acidic cation exchange resin, which could be released as soluble Pb(NO3)2 followed by precipitation as PbI2 for reuse, with a recycling efficiency of 99.2%. Thermal delamination disassembles the encapsulated modules with intact transparent conductors and cover glasses. The refabricated devices based on recycled lead iodide and recycled transparent conductors show comparable performance as devices based on fresh raw materials. Cost analysis shows this recycling technology is economically attractive.
Innovations in industrial automation, information and communication technology (ICT), renewable energy as well as monitoring and sensing fields have been paving the way for smart devices, which can acquire and convey information to the Internet. Since there is an ever-increasing demand for large yet affordable production volumes for such devices, printed electronics has been attracting attention of both industry and academia. In order to understand the potential and future prospects of the printed electronics, the present paper summarizes the basic principles and conventional approaches while providing the recent progresses in the fabrication and material technologies, applications and environmental impacts.
Increasing deployment of photovoltaics (PV) plants demands for cheap and fast inspection. A viable tool for this task is thermographic imaging by unmanned aerial vehicles (UAV). In this work, we develop a computer vision tool for the semi‐automatic extraction of PV modules from thermographic UAV videos. We use it to curate a dataset containing 4.3 million IR images of 107,842 PV modules from thermographic videos of seven different PV plants. To demonstrate its use for automated PV plant inspection, we train a ResNet‐50 to classify ten common module anomalies with more than 90% test accuracy. Experiments show that our tool generalizes well to different PV plants. It successfully extracts PV modules from 512 out of 561 plant rows. Failures are mostly due to an inappropriate UAV trajectory and erroneous module segmentation. Including all manual steps our tool enables inspection of 3.5 MWp to 9 MWp of PV installations per day, potentially scaling to multi‐gigawatt plants due to its parallel nature. While we present an effective method for automated PV plant inspection, we are also confident that our approach helps to meet the growing demand for large thermographic datasets for machine learning tasks, such as power prediction or unsupervised defect identification.
Effective recycling of spent perovskite solar modules will further reduce the energy requirements and environmental consequences of their production and deployment, thus facilitating their sustainable development. Here, through ‘cradle-to-grave’ life cycle assessments of a variety of perovskite solar cell architectures, we report that substrates with conducting oxides and energy-intensive heating processes are the largest contributors to primary energy consumption, global warming potential and other types of impact. We therefore focus on these materials and processes when expanding to ‘cradle-to-cradle’ analyses with recycling as the end-of-life scenario. Our results reveal that recycling strategies can lead to a decrease of up to 72.6% in energy payback time and a reduction of 71.2% in greenhouse gas emission factor. The best recycled module architecture can exhibit an extremely small energy payback time of 0.09 years and a greenhouse gas emission factor as low as 13.4 g CO2 equivalent per kWh; it therefore outcompetes all other rivals, including the market-leading silicon at 1.3–2.4 years and 22.1–38.1 g CO2 equivalent per kWh. Finally, we use sensitivity analyses to highlight the importance of prolonging device lifetime and to quantify the effects of uncertainty induced by the still immature manufacturing processes, changing operating conditions and individual differences for each module. Effective recycling of worn-out perovskite photovoltaic modules could improve their energy and environmental sustainability. The authors perform holistic life cycle assessments of selected solar cell architectures and provide guidelines for their future design.
Benefiting from low cost and simple synthesis, polythiophene (PT) derivatives are one of the most popular donor materials for organic solar cells (OSCs). However, polythiophene‐based OSCs still suffer from inferior power conversion efficiency (PCE) than those based on donor–acceptor (D–A)‐type conjugated polymers. Herein, a fluorinated polythiophene derivative, namely P4T2F‐HD, is introduced to modulate the miscibility and morphology of the bulk heterojunction (BHJ)‐active layer, leading to a significant improvement of the OSC performance. The Flory–Huggins interaction parameters calculated from the surface energy and differential scanning calorimetry results suggest that P4T2F‐HD shows moderate miscibility with the popular nonfullerene acceptor Y6‐BO (2,2′‐((2Z,2′Z)‐((12,13‐bis(2‐butyloctyl)‐3,9‐diundecyl‐12,13‐dihydro‐[1,2,5]thiadiazolo[3,4‐e]thieno[2′,3′:4′,5′]thieno[2′,3′:4,5]pyrrolo[3,2‐g]thieno[2′,3′:4,5]thieno[3,2‐b]indole‐2,10‐diyl)bis(methanylylidene))bis(5,6‐difluoro‐3‐oxo‐2,3‐dihydro‐1H‐indene‐2,1‐diylidene))dimalononitrile), while poly(3‐hexylthiophene) (P3HT) is very miscible with Y6‐BO. As a result, the P4T2F‐HD case forms desired nanoscale phase separation in the BHJ film while the P3HT case forms a completely mixed BHJ film, as revealed by transmission electron microscopy (TEM) and grazing‐incidence wide‐angle X‐ray scattering (GIWAXS). By optimizing the cathode interface and the morphology of the P4T2F‐HD:Y6‐BO films processed from nonhalogenated solvents, a new record PCE of 13.65% for polythiophene‐based OSCs is demonstrated. This work highlights the importance of controlling D/A interactions for achieving desired morphology and also demonstrates a promising OSC system for potential cost‐effective organic photovoltaics.
Recent advances in the development of organic photovoltaic (OPV) materials has led to significant improvements in device performance; now closing in on the 20% efficiency threshold. Despite these improvements in performance, the commercial viability of organic photovoltaic products remains elusive. In this perspective, the current limitations of high performing blends are uncovered, particularly focusing on the industrial upscaling considerations of these materials, such as synthetic scalability, active layer processing, and device stability. Moreover, a simplified metric, namely, the scalability factor (SF), is introduced to evaluate the scale‐up potential of specific OPV materials and blends thereof. Of the most popular molecular design strategies investigated in recent times, it is found that the use of Y‐series nonfullerene acceptors (NFAs) and synthetically simple materials, such as PTQ‐10 and ternary blends, are most effective at maximizing the efficiency without negatively impacting the SF. Furthermore, the improvements that are needed, in terms of device processability and stability, are considered for industrial scale‐up and final product application. Finally, an outlook of organic photovoltaics is provided both from a perspective of important research avenues and applications that can be exploited.
As graphene penetrates into industries, it is essential to mass produce high quality graphene sheets. New discoveries face formidable challenges in the marketplace due to the lack of proficient protocols to produce graphene on a commercial scale while maintaining its quality. Here, we present a conspicuous protocol for ultrafast exfoliation of graphite into high quality graphene on the sub-kilogram scale without the use of any intercalants, chemicals, or solvent. We show that graphite can be exfoliated using a plasma spray technique with high single-layer selectivity (∼85%) at a very high production rate (48 g/h). This is possible because of the inherent characteristics of the protocol which provides sudden thermal shock followed by two-stage shear. The exfoliated graphene shows almost no basal defect (Id/Ig: 0) and possesses high quality (C/O ratio: 21.2, sp2 %: ∼95%), an indication of negligible structural deterioration. The results were reproducible indicating the adeptness of the protocol. We provided several proofs-of-concept of plasma spray exfoliated graphene to demonstrate its utility in applications such as mechanical reinforcements; frictionless, transparent conductive coatings; and energy storage devices.
Organic solar cells have the potential to become the cheapest form of electricity, beating even silicon photovoltaics. This article summarizes the state of the art in the field, highlighting research challenges, mainly the need for an efficiency increase as well as an improvement in long‐term stability. It discusses possible current and future applications, such as building integrated photovoltaics or portable electronics. Finally, the environmental footprint of this renewable energy technology is evaluated, highlighting the potential to be the energy generation technology with the lowest carbon footprint of all.
Organic semiconductors (OSCs) promise to deliver next-generation electronic and energy devices that are flexible, scalable and printable. Unfortunately, realizing this opportunity is hampered by increasing concerns about the use of volatile organic compounds (VOCs), particularly toxic halogenated solvents that are detrimental to the environment and human health. Here, a cradle-to-grave process is reported to achieve high performance p-and n-type OSC devices based on indacenodithiophene and diketopyrrolopyrrole semiconducting polymers that utilizes aqueous-processes, fewer steps, lower reaction temperatures, a significant reduction in VOCs (>99%) and avoids all halogenated solvents. The process involves an aqueous mini-emulsion polymerization that generates a surfactant-stabilized aqueous dispersion of OSC nanoparticles at sufficient concentration to permit direct aqueous processing into thin films for use in organic field-effect transistors. Promisingly, the performance of these devices is comparable to those prepared using conventional synthesis and processing procedures optimized for large amounts of VOCs and halogenated solvents. Ultimately, the holistic approach reported addresses the environmental issues and enables a viable guideline for the delivery of future OSC devices using only aqueous media for synthesis, purification and thin-film processing.
Printed and hybrid integrated electronics produced from recycled and
renewable materials can reduce the depletion of limited material resources while
obtaining energy savings in small electronic applications and their energy storage.
In this work, bio-based poly(lactic acid) (PLA) and recycled polyethylene
terephthalate (rPET) were fabricated in film extrusion process and utilized as a
substrate in ultra-thin organic photovoltaics (OPV). In the device structure, metals
and metal oxides were replaced by printing PEDOT:PSS, carbon and amino
acid/heterocycles. Scalable, energy-efficient fabrication of solar cells resulted in
efficiencies up to 6.9% under indoor light. Furthermore, virgin-PET was replaced
with PLA and rPET in printed and hybrid integrated electronics where surface-mount
devices (SMD) were die-bonded onto silver-printed PLA and virgin-PET films to
prepare LED foils followed by an overmoulding process using the rPET and PLA. As a
result, higher relative adhesion of PLA-PLA interface was obtained in comparison
with rPET-PET interface. The obtained results are encouraging from the point of
utilization of scalable manufacturing technologies and natural/recycled materials in
printed and hybrid integrated electronics. Assessment showed a considerable decrease
in carbon footprint, about 10–85%, mainly achieved through replacing of silver,
virgin-PET and modifying solar cell structure. In outdoor light, the materials with
low carbon footprint can decrease energy payback times (EPBT) from ca. 250 days to
under 10 days. In indoor energy harvesting, it is possible to achieve EPBT of less
than 1 year. The structures produced and studied herein have a high potential of
providing sustainable energy solutions for example in IoT-related
technologies.
Transient electronics refers to an emerging class of advanced technology, defined by an ability to chemically or physically dissolve, disintegrate, and degrade in actively or passively controlled fashions to leave environmentally and physiologically harmless by-products in environments, particularly in bio-fluids or aqueous solutions. The unusual properties that are opposite to operational modes in conventional electronics for a nearly infinite time frame offer unprecedented opportunities in research areas of eco-friendly electronics, temporary biomedical implants, data-secure hardware systems, and others. This review highlights the developments of transient electronics, including materials, manufacturing strategies, electronic components, and transient kinetics, along with various potential applications.
A mess of plastic
It is not clear what strategies will be most effective in mitigating harm from the global problem of plastic pollution. Borrelle et al. and Lau et al. discuss possible solutions and their impacts. Both groups found that substantial reductions in plastic-waste generation can be made in the coming decades with immediate, concerted, and vigorous action, but even in the best case scenario, huge quantities of plastic will still accumulate in the environment.
Science , this issue p. 1515 , p. 1455
Conjugated polymers (CPs) possess a unique set of features setting them apart from other materials. These properties make them ideal when interfacing the biological world electronically. Their mixed electronic and ionic conductivity can be used to detect weak biological signals, deliver charged bioactive molecules, and mechanically or electrically stimulate tissues. CPs can be functionalized with various (bio)chemical moieties and blend with other functional materials, with the aim of modulating biological responses or endow specificity toward analytes of interest. They can absorb photons and generate electronic charges that are then used to stimulate cells or produce fuels. These polymers also have catalytic properties allowing them to harvest ambient energy and, along with their high capacitances, are promising materials for next‐generation power sources integrated with bioelectronic devices. In this perspective, an overview of the key properties of CPs and examination of operational mechanism of electronic devices that leverage these properties for specific applications in bioelectronics is provided. In addition to discussing the chemical structure–functionality relationships of CPs applied at the biological interface, the development of new chemistries and form factors that would bring forth next‐generation sensors, actuators, and their power sources, and, hence, advances in the field of organic bioelectronics is described.
Ultra‐lightweight solar cells have attracted enormous attention due to their ultra‐conformability, flexibility, and compatibility with applications including electronic skin or miniaturized electronics for biological applications. With the latest advancements in printing technologies, printing ultrathin electronics is becoming now a reality. This work offers an easy path to fabricate indium tin oxide (ITO)‐free ultra‐lightweight organic solar cells through inkjet‐printing while preserving high efficiencies. A method consisting of the modification of a poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) ink with a methoxysilane‐based cross‐linker (3‐glycidyloxypropyl)trimethoxysilane (GOPS)) is presented to chemically modify the structure of the electrode layer. Combined with plasma and solvent post‐treatments, this approach prevents shunts and ensures precise patterning of solar cells. By using poly(3‐hexylthiophene) along rhodanine‐benzothiadiazole‐coupled indacenodithiophene (P3HT:O‐IDTBR), the power conversion efficiency (PCE) of the fully printed solar cells is boosted up to 4.73% and fill factors approaching 65%. All inkjet‐printed ultrathin solar cells on a 1.7 µm thick biocompatible parylene substrate are fabricated with PCE reaching up to 3.6% and high power‐per‐weight values of 6.3 W g⁻¹. After encapsulation, the cells retain their performance after being exposed for 6 h to aqueous environments such as water, seawater, or phosphate buffered saline, paving the way for their integration in more complex circuits for biological systems.
The dye and pigment manufacturing industry is one of the most polluting in the world. Each year, over one million tons of petrochemical colorants are produced globally, the synthesis of which generates a large amount of waste. Naturally occurring, plant‐based dyes, on the other hand, are resource intensive to produce (land, water, energy), and are generally less effective as colorants. Between these two extremes would be synthetic dyes that are fully sourced from biomass‐derived intermediates. The present work describes the synthesis of such compounds, containing strong chromophores that lead to bright colors in the yellow to red region of the visible spectrum. The study was originally motivated by an early report of an unidentified halomethylfurfural derivative which resulted from hydrolysis in the presence of barium carbonate, now characterized as a butenolide of 5‐(hydroxymethyl)furfural (HMF). The method has been generalized for the synthesis of dyes from other biobased platform molecules, and a mechanism is proposed.
The chirality-controlled synthesis of single-walled carbon nanotubes (SWCNTs) is a major challenge facing current nanomaterials science. The surface-assisted bottom-up fabrication from unimolecular CNT seeds (precursors), which unambiguously predefine the chirality of the tube during the growth, appears to be the most promising approach. This strategy opens a venue towards controlled synthesis of CNTs of virtually any possible chirality by applying properly designed precursor molecules. However, synthetic access to the required precursor molecules remains practically unexplored because of their complex structure. Here, we report a general strategy for the synthesis of molecular seeds for the controlled growth of SWCNTs possessing virtually any desired chirality by combinatorial multi-segmental assembly. The suggested combinatorial approach allows facile assembly of complex CNT precursors (with up to 100 carbon atoms immobilized at strictly predefined positions) just in one single step from complementary segments. The feasibility of the approach is demonstrated on the synthesis of the precursor molecules for 21 different SWCNT chiralities utilizing just three relatively simple building blocks.
The application of polymer solar cells (PSCs) with n-type organic semiconductor as acceptor requires further improving powder conversion efficiency, increasing stability and decreasing cost of the related materials and devices. Here we report a simplified synthetic route for 4,4,9,9-tetrahexyl-4,9-dihydro-s-indaceno [1,2-b:5,6-b’] dithiophene by using the catalyst of amberlyst15. Based on this synthetic route and methoxy substitution, two low cost acceptors with less synthetic steps, simple post-treatment and high yield were synthesized. In addition, the methoxy substitution improves both yield and efficiency. The high efficiency of 13.46% was obtained for the devices with MO-IDIC-2F (3,9-bis(2-methylene-5 or 6-fluoro-(3-(1,1-dicyanomethylene)-indanone)-4,4,9,9-tetrahexyl-5,10-dimethoxyl-4,9-dihydro-s-indaceno[1,2-b:5,6-b’] dithiophene) as acceptor. Based on the cost analysis, the PSCs based on MO-IDIC-2F possess the great advantages of low cost and high photovoltaic performance in comparison with those PSCs reported in literatures. Therefore, MO-IDIC-2F will be a promising low cost acceptor for commercial application of PSCs.
There is a strong market driven need for processing organic photovoltaics from eco-friendly solvents. Water-dispersed organic semiconducting nanoparticles (NPs) satisfy these premises convincingly. However, the necessity of surfactants, which are inevitable for stabilizing NPs, is a major obstacle towards realizing competitive power conversion efficiencies for water-processed devices. Here, we report on a concept for minimizing the adverse impact of surfactants on solar cell performance. A poloxamer facilitates the purification of organic semiconducting NPs through stripping excess surfactants from aqueous dispersion. The use of surfactant-stripped NPs based on poly(3-hexylthiophene) / non-fullerene acceptor leads to a device efficiency and stability comparable to the one from devices processed by halogenated solvents. A record efficiency of 7.5% is achieved for NP devices based on a low-band gap polymer system. This elegant approach opens an avenue that future organic photovoltaics processing may be indeed based on non-toxic water-based nanoparticle inks.
Conventional semiconducting polymer synthesis typically involves transition metal-mediated coupling reactions that link aromatic units with single bonds along the backbone. Rotation around these bonds contributes to conformational and energetic disorder and therefore potentially limits charge delocalisation, whereas the use of transition metals presents difficulties for sustainability and application in biological environments. Here we show that a simple aldol condensation reaction can prepare polymers where double bonds lock-in a rigid backbone conformation, thus eliminating free rotation along the conjugated backbone. This polymerisation route requires neither organometallic monomers nor transition metal catalysts and offers a reliable design strategy to facilitate delocalisation of frontier molecular orbitals, elimination of energetic disorder arising from rotational torsion and allowing closer interchain electronic coupling. These characteristics are desirable for high charge carrier mobilities. Our polymers with a high electron affinity display long wavelength NIR absorption with air stable electron transport in solution processed organic thin film transistors.
Methylammonium lead iodide (MAPbI3) perovskite based solar cells have recently emerged as a serious competitor for large scale and low-cost photovoltaic technologies. However, since these solar cells contain toxic lead, a sustainable procedure for handling the cells after their operational lifetime is required to prevent exposure of the environment to lead and to comply with international electronic waste disposal regulations. Herein, we report a procedure to remove every layer of the solar cells separately, giving the possibility to selectively isolate the different materials. Besides isolating the toxic lead iodide, we show that the PbI2 can be reused for the preparation of new solar cells with comparable performance and in this way avoid lead waste. Furthermore, we show that the most expensive part of the solar cell, the conductive glass (FTO), can be reused several times without any reduction in the performance of the devices. With our simple recycling procedure, we address both the risk of contamination and the waste disposal of perovskite based solar cells, while further reducing the cost of the system. This brings perovskite solar cells one step closer to their introduction into commercial systems.
Electronic devices have advanced from their heavy, bulky origins to become smart, mobile appliances. Nevertheless, they remain rigid, which precludes their intimate integration into everyday life. Flexible, textile and stretchable electronics are emerging research areas and may yield mainstream technologies. Rollable and unbreakable backplanes with amorphous silicon field-effect transistors on steel substrates only 3 μm thick have been demonstrated. On polymer substrates, bending radii of 0.1 mm have been achieved in flexible electronic devices. Concurrently, the need for compliant electronics that can not only be flexed but also conform to three-dimensional shapes has emerged. Approaches include the transfer of ultrathin polyimide layers encapsulating silicon CMOS circuits onto pre-stretched elastomers, the use of conductive elastomers integrated with organic field-effect transistors (OFETs) on polyimide islands, and fabrication of OFETs and gold interconnects on elastic substrates to realize pressure, temperature and optical sensors. Here we present a platform that makes electronics both virtually unbreakable and imperceptible. Fabricated directly on ultrathin (1 μm) polymer foils, our electronic circuits are light (3 g m(-2)) and ultraflexible and conform to their ambient, dynamic environment. Organic transistors with an ultra-dense oxide gate dielectric a few nanometres thick formed at room temperature enable sophisticated large-area electronic foils with unprecedented mechanical and environmental stability: they withstand repeated bending to radii of 5 μm and less, can be crumpled like paper, accommodate stretching up to 230% on prestrained elastomers, and can be operated at high temperatures and in aqueous environments. Because manufacturing costs of organic electronics are potentially low, imperceptible electronic foils may be as common in the future as plastic wrap is today. Applications include matrix-addressed tactile sensor foils for health care and monitoring, thin-film heaters, temperature and infrared sensors, displays, and organic solar cells.
As the performance in terms of power conversion efficiency and operational stability for polymer and organic solar cells is rapidly approaching the key 10-10 targets (10 efficiency and 10 years of stability) the quest for efficient, scalable, and rational processing methods has begun. The 10-10 targets are being approached through consistent laboratory research efforts, which coupled with early commercial efforts have resulted in a fast moving research field and the dawning of a new industry. We review the roll-to-roll processing techniques required to bring the magnificent 10-10 targets into reality, using quick methods with low environmental impact and low cost. We also highlight some new targets related to processing speed, materials, and environmental impact.
The inherent flexibility afforded by molecular design has accelerated the development of a wide variety of organic semiconductors over the past two decades. In particular, great advances have been made in the development of materials for organic light-emitting diodes (OLEDs), from early devices based on fluorescent molecules to those using phosphorescent molecules. In OLEDs, electrically injected charge carriers recombine to form singlet and triplet excitons in a 1:3 ratio; the use of phosphorescent metal-organic complexes exploits the normally non-radiative triplet excitons and so enhances the overall electroluminescence efficiency. Here we report a class of metal-free organic electroluminescent molecules in which the energy gap between the singlet and triplet excited states is minimized by design, thereby promoting highly efficient spin up-conversion from non-radiative triplet states to radiative singlet states while maintaining high radiative decay rates, of more than 10(6) decays per second. In other words, these molecules harness both singlet and triplet excitons for light emission through fluorescence decay channels, leading to an intrinsic fluorescence efficiency in excess of 90 per cent and a very high external electroluminescence efficiency, of more than 19 per cent, which is comparable to that achieved in high-efficiency phosphorescence-based OLEDs.
Application-specific requirements for future lighting, displays and photovoltaics will include large-area, low-weight and mechanical resilience for dual-purpose uses such as electronic skin, textiles and surface conforming foils. Here we demonstrate polymer-based photovoltaic devices on plastic foil substrates less than 2 μm thick, with equal power conversion efficiency to their glass-based counterparts. They can reversibly withstand extreme mechanical deformation and have unprecedented solar cell-specific weight. Instead of a single bend, we form a random network of folds within the device area. The processing methods are standard, so the same weight and flexibility should be achievable in light emitting diodes, capacitors and transistors to fully realize ultrathin organic electronics. These ultrathin organic solar cells are over ten times thinner, lighter and more flexible than any other solar cell of any technology to date.
Solar cells based on polycrystalline Cu(In,Ga)Se(2) absorber layers have yielded the highest conversion efficiency among all thin-film technologies, and the use of flexible polymer films as substrates offers several advantages in lowering manufacturing costs. However, given that conversion efficiency is crucial for cost-competitiveness, it is necessary to develop devices on flexible substrates that perform as well as those obtained on rigid substrates. Such comparable performance has not previously been achieved, primarily because polymer films require much lower substrate temperatures during absorber deposition, generally resulting in much lower efficiencies. Here we identify a strong composition gradient in the absorber layer as the main reason for inferior performance and show that, by adjusting it appropriately, very high efficiencies can be obtained. This implies that future manufacturing of highly efficient flexible solar cells could lower the cost of solar electricity and thus become a significant branch of the photovoltaic industry.
The rapid growth of personal electronics has promoted a surge of e-waste worldwide. Among the e-waste stream, waste printed circuit boards (WPCBs) contain a lot of recyclable valuable metals that can incentivize the recycling operation when recovered. This pedagogical exercise demonstrates a simple electrocatalytic metal recovery strategy that works at room temperature and atmospheric pressure. Students can complete the exercise within 1.5-2 h and get to learn about electrocatalytic reactions and their parameters. The reaction can be powered by a couple of 1.5 V AA batteries and an electrolyte chemically similar to automobile antifreeze. Using quotidian objects can help students connect their laboratory learning with their daily lives. In addition to teaching electrochemistry concepts, we hope this exercise can raise awareness of the substantial increase of e-waste in recent years. © 2022 American Chemical Society and Division of Chemical Education, Inc.
As ultrathin organic solar cells hit new efficiency records, researchers see green energy potential in surprising places
Mixed plastics waste represents an abundant and largely untapped feedstock for the production of valuable products. The chemical diversity and complexity of these materials, however, present major barriers to realizing this opportunity. In this work, we show that metal-catalyzed autoxidation depolymerizes comingled polymers into a mixture of oxygenated small molecules that are advantaged substrates for biological conversion. We engineer a robust soil bacterium, Pseudomonas putida, to funnel these oxygenated compounds into a single exemplary chemical product, either β-ketoadipate or polyhydroxyalkanoates. This hybrid process establishes a strategy for the selective conversion of mixed plastics waste into useful chemical products.
Electronic waste, with printed circuit boards (PCBs) at its heart, is the fastest-growing category of hazardous solid waste in the world. New materials, in particular biobased materials, show great promise in solving some of the sustainability and toxicity problems associated with PCBs, although several challenges still prevent their practical application.
The recent trend of some countries opting to ban the sale of new gasoline and diesel vehicles has led to an increase in the use of electric vehicles and automated driving. In an automobile, windows are the largest source of heat energy between the interior and exterior of the vehicle. By modulating the window material, we can precisely control the amount of heat from sunlight that is allowed to enter the car, reduce the load on heating and cooling. Thus, suppress the energy loss associated with air conditioning by introducing technology to control heat energy in windows, which can also help reduce electricity costs. To this end, our research group has been developing complementary electrochromic devices (ECDs) using Prussian blue and tungsten oxide, which consist of nanoparticles dispersed in aqueous solvents to make inks. Spin coating is used for film deposition at the laboratory level; however, it has a major limitation in terms of uniformity. Therefore, in this study, we fabricated functional thin films by using these inks with slit coating, which is a commercial process. The results obtained confirm that slit coating can be used to deposit approximately 1-μm-thick films as fast as within 20 s and even on large G2 size substrates; further, the uniformity of the films measured based on chromaticity and haze is high. In addition, this effect improves the response time of the ECD. As a future direction, this can be applied to flexible ECD, etc.
Polymeric planarization layers play a pivotal role in OLED displays’ thin‐film encapsulation. With its low material consumption, deposition geometry flexibility, high throughput, and reliability, inkjet printing is the preferred deposition technology for such films.
Molecular doping has recently been shown to improve the operating characteristics of organic photovoltaics (OPVs). Here, we prepare neutral Diquat (DQ) and use it as n-dopant to improve the performance of state-of-the-art OPVs. Adding DQ in ternary bulk-heterojunction (BHJ) cells based of PM6:Y6:PC71BM is found to consistently increase their power conversion efficiency (PCE) from 16.7 to 17.4%. Analyses of materials and devices reveal that DQ acts as n-type dopant and morphology modifier for the BHJ leading to observable changes in its surface topography. The resulting n-doped BHJs exhibit higher optical absorption coefficients, balanced ambipolar transport, longer carrier lifetimes and suppressed bimolecular recombination, which are ultimately responsible for the increased PCE. The use of DQ was successfully extended to OPVs based on PM6:BTP-eC9:PC71BM for which a maximum PCE of 18.3% (uncertified) was achieved. Our study highlights DQ as a promising dopant for application in next generation organic solar cells.
RGB printing method has been widely regarded as a potential tool for manufacturing high resolution, large size OLED applications, with the help of recent progresses of soluble OLED materials and ink‐jet printing equipment. However, there are still technical hurdles which remain in order for inkjet‐printed OLED displays to move from prototype to mass production scale.
In this report, recent R&D trends will be reviewed of device performances, ink‐jet printing equipment, as well as inkjet‐printed OLED products recently demonstrated by display panel makers for various applications. Moreover, key technical issues will be discussed to be overcome in order for mass production, such as an ink formulation, a high resolution ink‐jet printing, inter‐mixing between printed layers, thickness uniformity of printed layers, etc.
Lastly, our recent progress will be presented, of a power consumption, color gamut, and lifetime of inkjet‐printed panel with pixel resolution over 200ppi.
Organic semiconductors are solution-processable, lightweight and flexible and are increasingly being used as the active layer in a wide range of new technologies. The versatility of synthetic organic chemistry enables the materials to be tuned such that they can be incorporated into biological sensors, wearable electronics, photovoltaics and flexible displays. These devices can be improved by improving their material components, not only by developing the synthetic chemistry but also by improving the analytical and computational techniques that enable us to understand the factors that govern material properties. Judicious molecular design provides control of the semiconductor frontier molecular orbital energy distribution and guides the hierarchical assembly of organic semiconductors into functional films where we can manipulate the properties and motion of charges and excited states. This Review describes how molecular design plays an integral role in developing organic semiconductors for electronic devices in present and emerging technologies. Many present and emerging electronic devices make use of organic semiconductors in view of their readily tuneable molecular and electronic structures. This Review describes the importance of analytical and computational tools in studying the molecules as well as their hierarchical self-assemblies, in which the motion of charges and excited states govern device properties.
Electronic waste is the fastest growing category of hazardous solid waste in the world. Addressing the problem will require international collaboration, economic incentives that protect labour, and management approaches that minimize adverse impacts on the environment and human health.
Non-fullerene acceptors based organic photovoltaics (OPVs) have attracted considerable attention in the last decade due to their great potential to realize high-power conversion efficiencies. To achieve higher performance OPVs, the fundamental challenges are in enabling efficient charge separation/transport and a low voltage loss at the same time. Here, we have designed and synthesized a new class of non-fullerene acceptor, Y6, that employs an electron-deficient-core-based central fused ring with a benzothiadiazole core, to match with commercially available polymer PM6. By this strategy, the Y6-based solar cell delivers a high-power conversion efficiency of 15.7% with both conventional and inverted architecture. By this research, we provide new insights into employing the electron-deficient-core-based central fused ring when designing new non-fullerene acceptors to realize improved photovoltaic performance in OPVs.
Solution processing of OLED is desirable because it allows for large area OLED displays with low manufacturing cost. Historically the device performance achievable with solution processing lagged that of evaporation. DuPont has focused on developing OLED materials for soluble technologies, as well as working with our partners on our proprietary printing process. Our performance data shows that with our latest generation materials and process steps, ink‐jet printed device performance suitable for TV application can now be achieved.
We demonstrate continuous roll-to-roll (R2R) fabrication of single junction and tandem organic photovoltaic (OPV) cells on flexible plastic substrates employing a system that integrates organic deposition by high vacuum thermal evaporation (VTE) and low pressure organic vapor phase deposition (OVPD). By moving the substrate from chamber to chamber and then depositing films on stationary substrates, we achieve power conversion efficiencies of PCE = 8.6 ± 0.3% and 8.9 ± 0.2% for the single junction and tandem cells, respectively. Single junction OPVs are also fabricated on a continuously translating substrate at 0.3 cm/s, to achieve PCE = 8.5 ± 0.2%. Thin films grown on translating substrates by OVPD show <3% thickness non-uniformity and 0.66 nm root mean square surface roughness, similar to that obtained by VTE. Our results suggest that R2R film deposition comprising multiple vapor deposition technologies is a promising method for rapid speed and continuous manufacturing of high quality, small molecular weight organic electronic materials.
Organic light-emitting diodes (OLEDs) produced from metal complexes play an important role in modern electroluminescent devices. While OLEDs are being used in display various applications such as TVs, smartphones and wearables already, a drastic increase in the production volume in the next years is being expected as soon as OLED lighting applications and printed OLEDs hit the market. Given that thus far, phosphorescent iridium compounds are required to make these products, sustainability issues are imminent. To review viable alternatives, we highlight the current status of sustainable metal complexes with a special focus on copper and zinc complexes. Ligand structures and complex preparation were highlighted. We also briefly address features like cooperativity, chirality, and printing.
Engineered nanomaterials (ENMs) are being incorporated into a variety of consumer products due to unique properties that offer a variety of advantages over bulk materials. Understanding of the nano-specific risk associated with nano-enabled technologies, however, continues to lag behind research and development, registration with regulators, and commercialization. One example of a nano-enabled technology is nanosilver ink, which can be used in commercial ink-jet printers for the development of low-cost printable electronics. This investigation utilizes a tiered EHS framework to evaluate the potential nano-specific release, exposure and hazard associated with typical use of both nanosilver ink and printed circuits. The framework guides determination of the potential for ENM release from both forms of the technology in simulated use scenarios, including spilling of the ink, aqueous release (washing) from the circuits and UV light exposure. The as-supplied ink merits nano-specific consideration based on the presence of nanoparticles and their persistence in environmentally-relevant media. The material released from the printed circuits upon aqueous exposure was characterized by a number of analysis techniques, including ultracentrifugation and single particle ICP-MS, and the results suggest that a vast majority of the material was ionic in nature and nano-specific regulatory scrutiny may be less relevant.
Perovskite solar cells based on CH3NH3PbI3 and related materials have reached impressive efficiencies that, on a lab scale, can compete with established solar cell technologies, at least in short-term observations. Despite frequently voiced concerns about the solubility of the lead salts that make up the absorber material, several life cycle analyses have come to overall positive conclusions regarding the environmental impact of perovskite solar cell (PSC) production. Their particularly short energy payback time (EBPT) in comparison to other established PV technologies makes them truly competitive. Several studies have identified valuable components such as FTO, gold and high temperature processes as the most significant contributors to the environmental impact of PSCs. Considering these findings, we have developed a rapid dismantling process allowing the recovery of all major components, saving raw materials, energy and production time in the fabrication of recycled PSCs. We demonstrate that the performance of PSCs fabricated from recycled substrates can compete with that of devices fabricated from virgin materials.
Recent developments in organic photovoltaic technology demonstrate the possibility of easily printable, light, thin, and flexible solar panels with fast manufacturing times. Prior life-cycle assessment studies show potential for organic photovoltaics to lower the environmental footprint and shorten the energy and carbon payback times compared to conventional silicon during the production of a solar cell on a watt-for-watt basis. This study extends such analyses beyond the manufacturing stage and evaluates the prospective cradle-to-grave life-cycle impacts of organic photovoltaics compared with conventional ones. Two systems (solar rooftop array and portable solar charger) were chosen to illustrate how different product integrations, duration of use and disposal routes influence potential environmental benefits of organic photovoltaics while informing researchers on the prospects for continued development and scaling-up this technology. The results of the life-cycle assessment showed that environmental benefits for organic photovoltaics extend beyond the manufacture of the photovoltaic panels, with baseline cradle-to-grave impacts for both long-term uses (rooftop arrays) and short-term uses (portable chargers) on average 55% and 70% lower than silicon devices, respectively. These results demonstrate that further reductions can be leveraged by integrating organic photovoltaics into simpler devices that take advantage of their flexibility and ability to be used in applications that are less constrained by conventional technology. For example, organic photovoltaic charging units showed life-cycle impacts more than 39-89% lower than silicon along with energy and carbon payback times as short as 220 and 118 days, respectively.
Biocompatible-ingestible electronic circuits and capsules for medical diagnosis and monitoring are currently based on traditional silicon technology. Organic electronics has huge potential for developing biodegradable, biocompatible, bioresorbable, or even metabolizable products. An ideal pathway for such electronic devices involves fabrication with materials from nature, or materials found in common commodity products. Transistors with an operational voltage as low as 4-5 V, a source drain current of up to 0.5 mu A and an on-off ratio of 3-5 orders of magnitude have been fabricated with such materials. This work comprises steps towards environmentally safe devices in low-cost, large volume, disposable or throwaway electronic applications, such as in food packaging, plastic bags, and disposable dishware. In addition, there is significant potential to use such electronic items in biomedical implants.
Indium is an important by-product of zinc metal processing operations. Indium and other metal values are recovered during the production of primary commodities such as zinc by means of complex procedures, many of which are proprietary to each producer. One zinc recovery method consists of the Waelz process followed by leaching and purification prior to electrolytic recovery of zinc as cathodes and subsequent containment of the indium fraction in residues. Related processes for recovery of lead and tin from smelters and refineries also provide indium and other compounds. Indium may be associated with other valuable elements such as vanadium, thallium, gallium and germanium, and cadmium. Typical sulphide-bearing host minerals consist of Sphalerite, Galena, and Chalcopyrite. The igneous intrusions in sedimentary formations may include other base metals such as copper, cobalt, and noble metals consisting of gold, silver, and platinum group metals. The review serves to assimilate the major highlights of this somewhat rare metal which has both strategic importance and is well suited to electronic applications. On a global basis, the writers are aware of 30 producers dedicated to the commercial production of indium metal. Countries such as Belgium, Canada, China, France, Japan, Russia, and the USA are the largest producers of indium while about ten other countries contribute smaller quantities for worldwide consumption. The supply and demand of pure indium products during the past 40 years has been erratic and subject to wide fluctuations in delivered price. The paper describes the sources and established industrial processes for recovery of indium originating from sulphidic materials and process reverts.
We report a comprehensive study of transparent and conductive silver nanowire (Ag NW) electrodes, including a scalable fabrication process, morphologies, and optical, mechanical adhesion, and flexibility properties, and various routes to improve the performance. We utilized a synthesis specifically designed for long and thin wires for improved performance in terms of sheet resistance and optical transmittance. Twenty Omega/sq and approximately 80% specular transmittance, and 8 ohms/sq and 80% diffusive transmittance in the visible range are achieved, which fall in the same range as the best indium tin oxide (ITO) samples on plastic substrates for flexible electronics and solar cells. The Ag NW electrodes show optical transparencies superior to ITO for near-infrared wavelengths (2-fold higher transmission). Owing to light scattering effects, the Ag NW network has the largest difference between diffusive transmittance and specular transmittance when compared with ITO and carbon nanotube electrodes, a property which could greatly enhance solar cell performance. A mechanical study shows that Ag NW electrodes on flexible substrates show excellent robustness when subjected to bending. We also study the electrical conductance of Ag nanowires and their junctions and report a facile electrochemical method for a Au coating to reduce the wire-to-wire junction resistance for better overall film conductance. Simple mechanical pressing was also found to increase the NW film conductance due to the reduction of junction resistance. The overall properties of transparent Ag NW electrodes meet the requirements of transparent electrodes for many applications and could be an immediate ITO replacement for flexible electronics and solar cells.