Guillermo Bazan

Guillermo Bazan
University of California, Santa Barbara | UCSB · Department of Chemistry and Biochemistry

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769
Publications
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60,310
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Publications

Publications (769)
Article
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Microbial electrosynthesis – using renewable electricity to stimulate microbial metabolism – holds the promise of sustainable chemical production. A key limitation hindering performance are slow electron transfer rates at biotic‐abiotic interfaces. Here, we rationally design and synthesize a new n‐type conjugated polyelectrolyte and demonstrate its...
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Doping has shown very promising potential in endowing room-temperature phosphorescence (RTP) properties of organic phosphors with minimal effort. In this work, we report a new isomer design and doping strategy that is applicable to dibenzothiophene (DBT) and its derivatives. Three isomers were synthesized to study the dopant effect on enhancing RTP...
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Conjugated polyelectrolytes (CPEs) are characterized by an electronically delocalized backbone bearing ionic functionalities. These features lead to properties relevant for use in energy-storing pseudocapacitor devices, including ionic conductivity, water processability, gel-formation, and formation of polaronic species stabilized by electrostatic...
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We report the design and synthesis of the NIR‐II emissive conjugated oligoelectrolyte COE‐BBT. COE‐BBT has a solubility in aqueous media greater than 50 mg mL−1, low toxicity and a propensity to intercalate lipid bilayers, wherein it exhibits a higher emission quantum yields relative to aqueous media. Addition of COE‐BBT to cells provides two emiss...
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Organic solar cells that are transparent to visible light are highly desirable for applications such as window treatments or solar greenhouse panels. A key challenge is to simultaneously transmit most photons between 400 and 700 nm while retaining a high short‐circuit current and power conversion efficiency (PCE). Here, we report organic bulk heter...
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Cationic conjugated oligoelectrolytes (COEs) are a class of compounds that can be tailored to achieve relevant in vitro antimicrobial properties with relatively low cytotoxicity against mammalian cells. Three distyrylbenzene‐based COEs were designed containing amide functional groups on the side chains. Their properties were compared to two represe...
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Successful practical implementation of bioelectrochemical systems requires developing affordable electrode structures that promote efficient electrical communication with microbes. Recent efforts have centered on immobilizing bacteria with organic semiconducting polymers on electrodes via electrochemical methods. This approach creates a fixed bioco...
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Conducting polymer hydrogels (CPHs) are an attractive class of materials that synergize the electrical properties of organic semiconductors with the physical properties of hydrogels. Of particular interest is the implementation of CPHs as electrode materials for electrochemical energy storage by taking advantage of redox-tunable conjugated backbone...
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The use of non-fullerene acceptors (NFAs) in organic solar cells has led to power conversion efficiencies as high as 18%1. However, organic solar cells are still less efficient than inorganic solar cells, which typically have power conversion efficiencies of more than 20%2. A key reason for this difference is that organic solar cells have low open-...
Preprint
Following the 1 release of the “Emerging PV reports” , the best achievements in the performance of emerging photovoltaic devices in diverse emerging photovoltaic research subjects are summarized, as reported in peer-reviewed articles in academic journals since August 2020. Updated graphs, tables and analyses are provided with several performance pa...
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Infections caused by Gram-positive bacteria, especially those able to invade and survive in host cells, threaten human health severely. It is therefore highly desirable to develop therapeutics that can selectively target and kill intracellular Gram-positive pathogens with minimal toxicity to host cells. Herein, it is described that the aggregation-...
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Silver, in the form of nanostructures, is widely employed as an antimicrobial agent. The origin of the biocidal mechanism has been elucidated in the last decades, originating from silver cation release due to oxidative dissolution followed by cellular uptake of silver ions, a process that causes a severe disruption of bacterial metabolism, leading...
Preprint
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New antibiotics are needed to battle growing antibiotic resistance, but the development process from hit, to lead, and ultimately to a useful drug, takes decades. Although progress in molecular property prediction using machine-learning methods has opened up new pathways for aiding the antibiotics development process, many existing solutions rely o...
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Conjugated polyelectrolytes (CPEs), comprised of conjugated backbones and pendant ionic functionalities, are versatile organic materials with diverse applications. However, the myriad of possible molecular structures of CPEs render traditional, trial-and-error materials discovery strategy impractical. Here, we tackle this problem using a data-centr...
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The effect of the cross‐coupling catalyst tetrakis(triphenylphosphine)palladium(0) (Pd(PPh3)4) on the performance of a model organic bulk‐heterojunction solar cell composed of a blend of poly([2,6′‐4,8‐di(5‐ethylhexylthienyl)benzo[1,2‐b;3,3‐b]dithiophene]{3‐fluoro‐2[(2‐ethylhexyl)carbonyl]thieno[3,4‐b]thiophenediyl}) (PTB7‐Th) donor and 3,9‐bis(2‐m...
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Power generation and charge storage devices are commonly uncoupled when it comes to the design of materials relevant for their fabrication. Here, it is demonstrated that the biotic–abiotic composite comprising the self‐doped conjugated polyelectrolyte CPE‐K and electrogenic bacteria Shewanella oneidensis MR‐1 can reversibly switch its function betw...
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Continuously enhanced photoresponsivity and suppressed dark/noise current combinatorially lead to the recent development of high-detectivity organic photodetectors with broadband sensing competence. Despite the achievements, reliable photosensing enabled by organic photodetectors (OPDs) still faces challenges. Herein, we call for heed over a univer...
Preprint
Full-text available
Silver, especially in the form of nanostructures, is widely employed as an antimicrobial agent in a large range of commercial products. The origin of the biocidal mechanism has been elucidated in the last decades, and most likely originates from silver cation release due to oxidative dissolution followed by cellular uptake of silver ions, a process...
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Correction for ‘Semiconducting polymer contributes favorably to the Seebeck coefficient in multi-component, high-performance n-type thermoelectric nanocomposites’ by Junhui Tang et al. , J. Mater. Chem. A , 2020, 8 , 9797–9805, DOI: 10.1039/d0ta02388d.
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Simulation of electronic dynamics in realistically large molecular systems is a demanding task that has not yet achieved the same level of quantitative prediction already realized for its static counterpart. This is particularly true for processes occurring beyond the Born–Oppenheimer regime. Non-adiabatic molecular dynamics (NAMD) simulations suff...
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The relationship of the temperature–light intensity dependence of open‐circuit voltage Voc in nonfullerene‐based organic solar cells with their material characteristics and multimechanism recombination parameters is described. The systematic variation of the effective bandgap Eg,eff and the electrode layers allows the observation of different relat...
Article
Amyloid aggregation of tau protein is implicated in neurodegenerative diseases, yet its facilitating factors are poorly understood. Recently, tau has been shown to undergo liquid liquid phase separation (LLPS) both in vivo and in vitro. LLPS was shown to facilitate tau amyloid aggregation in certain cases, while independent of aggregation in other...
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The short-circuit current (Jsc) of organic solar cells is defined by the interplay of exciton photogeneration in the active layer, geminate and non-geminate recombination losses and free charge carrier extraction. The method proposed in this work allows the quantification of geminate recombination and the determination of the mobility-lifetime prod...
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The performance of solution-processed organic semiconductor devices is heavily influenced by the morphology of the active layer. Film formation is a complex process, with the final morphology being the result of the interplay between processing parameters and molecular properties, which is only poorly understood. Here, we investigate the influence...
Article
Fluorescence-based sensing powers laboratory-based bioanalytical systems. However, translating fluorescence-based bioanalytical sensing to benchtop or portable commercial platforms poses several technical challenges, including long-term sensor stability and fabrication complexity. To overcome such challenges, we designed, fabricated, and validated...
Preprint
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The power conversion efficiencies (PCEs) of organic solar cells (OSCs) using non-fullerene acceptors (NFAs) have now reached 18%. However, this is still lower than inorganic solar cells, for which PCEs >20% are commonplace. A key reason is that OSCs still show low open-circuit voltages (Voc) relative to their optical band gaps, attributed to non-ra...
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It is shown that Gram‐type differentiation, an essential tool in microbiology, can now be easily accomplished by using the chain‐elongated conjugated oligoelectrolyte COE‐S6. Specifically, COE‐S6 can be used as a fluorescent membrane probe that distinguishes between Gram‐negative and Gram‐positive bacteria in a single step. Confocal microscopy of l...
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In article number 2004068, Jamie Hinks, Guillermo C. Bazan, and co‐workers develop a membrane‐specific fluorescent dye that selectively stains Gram‐positive bacteria based on a conjugated oligoelectrolyte molecular structure. The conjugated oligoelectrolyte does not exhibit antimicrobial characteristics and enables in‐situ visualization of individu...
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Gain photodetectors offer large photoresponse towards small optical signals. Despite having achieved high external quantum efficiency (EQE), current gain organic photodetectors (OPDs) generally suffer from narrow spectral sensitivity, slow response time and/or large operating voltage for achieving a favorable gain. So far, strategies tackling one o...
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Organic semiconductors (OSCs) are of fundamental and technological interest, owing to their properties and functions in a range of optoelectronic devices, including organic light-emitting diodes, organic photovoltaics and organic field-effect transistors, as well as emerging technologies, such as bioelectronic devices. The solid-state organization...
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PCPDTBT‐SO3K (CPE‐K), a conjugated polyelectrolyte, is presented as a mixed conductor material that can be used to fabricate high transconductance accumulation mode organic electrochemical transistors (OECTs). OECTs are utilized in a wide range of applications such as analyte detection, neural interfacing, impedance sensing, and neuromorphic comput...
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In this work, we aim to provide a better understanding for the reasons behind electron transfer inefficiencies between electrogenic bacterium and the electrode in microbial fuel cells. We do so by using a self-doped conjugated polyelectrolyte (CPE) as the electrode surface, onto which Geobacter sulfurreducens is placed, then using conductive atomic...
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A series of cationic conjugated oligoelectrolytes (COEs) was designed to understand how variations in molecular dimensions impact the relative activity against bacteria and mammalian cells. These COEs kept a consistent distyrylbenzene framework but differed in the length of linker between the core and the cationic site and the length of substitute...
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A new narrow bandgap non-fullerene electron acceptor was designed, synthesized, and characterized for near-infrared organic photovoltaics. This acceptor was compared to a structurally similar compound with systematically modified side chains, and a series of solar cells were fabricated, employing the common donor polymers PTB7-Th and PBDBT. The dev...
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Composites, in which two or more material elements are combined to provide properties unattainable by single components, have a historical record dating to ancient times. Few include a living microbial community as a key design element. A logical basis for enabling bioelectronic composites stems from the phenomenon that certain microorganisms trans...
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Combining Shewanella oneidensis MR‐1 with the self‐doped conjugated polyelectrolyte CPE‐K leads to conductive networks that allow transfer of extracellular electron equivalents to an external gold electrode. In article 1908178, Guillermo C. Bazan and co‐workers show that 3D living biocomposites incorporating electrogenic bacteria and conductive gel...
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Even though significant breakthroughs with over 18% power conversion efficiencies (PCEs) in polymer:non‐fullerene acceptor (NFA) bulk heterojunction organic solar cells (OSCs) have been achieved, not many studies have focused on acquiring a comprehensive understanding of the underlying mechanisms governing these systems. This is because it can be c...
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We present our study of conjugated polymer-small molecule (SM)-non-fullerene ternary organic solar cells (OSCs), which employs conjugated polymer PTB7-Th and small molecule p-DTS(FBTTh2)2 as donors and non-fullerene molecule IEICO-4F as an acceptor. It is observed that the power conversion efficiency (PCE) of ∼10.9% for PTB7-Th: p-DTS(FBTTh2)2: IEI...
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Ambipolar polymer semiconductors are among the most ubiquitous semiconductors used for high mobility organic field-effect transistors. However, since ambipolar polymer semiconductors are capable of conducting both holes and electrons in typical organic-field effect transistor architectures, these devices never reach a well-defined off state, limiti...
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n-Type semiconducting polymers bearing high Seebeck coefficient (S) have been seldom employed in organic-inorganic thermoelectric nanocomposites (TENCs). Herein we illustrate how to exploit an n-type semiconducting polymer to fabricate TENCs comprising N2200 and metallic Co NWs, in which N2200 contributes significantly to the S of the TENCs. The TE...
Article
The conjugated polyelectrolyte poly[2,6-(4,4-bis-potassium butanylsulfonate-4H-cyclopenta-[2,1-b;3,4-b’]- dithiophene)-alt-4,7-(2,1,3-benzothiadiazole)] (PCPDTBTSO3K, or CPE-K) is part of a unique class of organic semiconducting polymers that are soluble in water and become doped in the presence of a proton source. One of these proton sources is wa...
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Ordered domains play a central role in determining the properties of organic semiconductors, and thereby the performance of their devices. The molecules in these ordered domains are often characterized by planar backbone conformations. We investigate the influence of backbone planarity on the propensity to form ordered structures using a pair of mo...
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A series of A−π−D−π–A type nonfullerene acceptors (NFAs) was designed and synthesized with the goal of optimizing light absorption and energy losses in near-infrared (NIR) organic solar cells (OSCs) principally through the use of side chain engineering. Specific molecules include p-IO1, o-IO1, p-IO2, and o-IO2 with optical bandgaps of 1.34 eV, 1.28...
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The growing number of applications of doped organic semiconductors drives the development of highly conductive and stable materials. Lack of understanding about the formation and properties of mobile charges limits the ability to improve material design. Thus the largely unexplored photophysics of doped systems are addressed here to gain insights a...
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Conjugated oligoelectrolytes (COEs) are emerging antimicrobials with broad spectrum activity against Gram positive and Gram negative bacteria as well as fungi. Our previous in vitro evolution studies using Enterococcus faecalis grown in the presence of two related COEs (COE1-3C and COE1-3Py) led to the emergence of mutants (changes in liaF and liaR...
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Carbapenem‐resistant Gram‐negative bacteria (GNB) are heading the list of pathogens for which antibiotics are the most critically needed. Many antibiotics are either unable to penetrate the outer‐membrane or are excluded by efflux mechanisms. Here, we report a cationic block beta‐peptide (PAS8‐ b ‐PDM12) that reverses intrinsic antibiotic resistanc...
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Das glykosylierte kationische β-Peptid PAS8-b-PDM12 sensibilisiert die wirkstoffresistenten Gram-negativen ESKAPE-Bakterien für mehrere Antibiotika, indem es die Penetration durch die Außenmembran erleichtert und die Effluxpumpsysteme deaktiviert. Dies ebnet Wege für neue Kombinationstherapien für lebensbedrohliche bakterielle Infektionen. Abstrac...
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Sensitive detection of near‐infrared (NIR) light enables many important applications in both research and industry. Current organic photodetectors suffer from low NIR sensitivity typically due to early absorption cutoff, low responsivity, and/or large dark/noise current under bias. Herein, organic photodetectors based on a novel ultranarrow‐bandgap...
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Precise doping of organic semiconductors allows control over the conductivity of these materials, an essential parameter in electronic applications. Although Lewis acids have recently shown promise as dopants for solution-processed polymers, their doping mechanism is not yet fully understood. In this study, we found that B(C6F5)3 is a superior dopa...
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Recent advances in n‐type organic–inorganic thermoelectric nanocomposites (TENCs) based on carbon nanotubes and inorganic nanocrystals are reviewed by Lidong Chen, Guillermo C. Bazan. Ziqi Liang, and co‐workers in article number 1800943. A variety of effective strategies for enhancing thermoelectric performance in n‐type TENCs are highlighted. An o...
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The treatment of bacterial infections is hindered by the presence of biofilms and metabolically inactive persisters. Here, we report the synthesis of an enantiomeric block co-beta-peptide, poly(amido-D-glucose)-block-poly(beta-L-lysine), with high yield and purity by one-shot one-pot anionic-ring opening (co)polymerization. The co-beta-peptide is b...