
Juan A AntaPablo de Olavide University | UPO · Department of Physical, Chemical and Natural Systems
Juan A Anta
Ph. D. Physical Chemistry
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209
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January 1993 - December 1996
January 1993 - December 1996
January 2000 - December 2012
Publications
Publications (209)
Metal halide perovskite solar cells (MHPSCs) hold great promise related to their high efficiency and low fabrication costs, but their long-term stability under environmental conditions remains a major challenge. In this study, we demonstrate an effective protection strategy to enhance the stability of MHPSCs through the incorporation of a double pa...
Perovskite solar cells (PSCs) continue to be the “front runner” technology among emerging photovoltaic devices in terms of power conversion efficiency and versatility of applications. However, improving stability and understanding their relationship with their ionic–electronic transport mechanisms continue to be challenging. In this work, a case st...
Dye‐sensitized solar cells (DSCs) are being considered as a promising technology for indoor photovoltaics due to their exceptional performance in ambient environments and under low illumination intensity conditions. The efficiency of electron collection in the photoanode of a DSC is determined by a delicate balance between electronic transport with...
Metal halide perovskites have brought about a disruptive shift in the field of third-generation photovoltaics. Their potential as remarkably efficient solar cell absorbers was first demonstrated in the beginning of the 2010s. However, right from their inception, persistent challenges have impeded the smooth adoption of this technology in the indust...
ZnO-based dye-sensitized solar cells exhibit lower efficiencies than TiO2-based systems despite advantageous charge transport dynamics and versatility in terms of synthesis methods, which can be primarily ascribed to compatibility issues of ZnO with the dyes and the redox couples originally optimized for TiO2. We evaluate the performance of solar c...
Photochromic dyes possess unique properties that can be exploited in different domains, including optics, biomedicine and optoelectronics. Herein, we explore the potential of photochromic spiro-indoline naphthoxazine (SINO) and naphthopyran (NIPS) for application in photovoltaics. We designed and synthesized four new photosensitizers with a donor-p...
A combination of experimental studies and drift‐diffusion modelling has been used to investigate the appearance of inverted hysteresis, where the area under the J‐V curve for the reverse scan is lower than in the forward scan, in perovskite solar cells. We find that solar cells in the p‐i‐n configuration show inverted hysteresis at a sufficiently h...
Impedance spectroscopy (IS) is a straightforward experimental technique that is commonly used to obtain information about the physical and chemical characteristics of photovoltaic devices. However, the non-standard physical behaviour of perovskite solar cells (PSCs), which are heavily influenced by the motion of mobile ion vacancies, has hindered e...
Ion migration mechanisms are often behind degradation pathways in perovskite solar cells under operating conditions. In this work we look at the effect of non-stoichiometric compositions in mixed caesium/formamidinium inverted perovskite solar cells (PSC) on their performance and short-term degradation. From impedance measurements and drift-diffusi...
Perovskite have had a great impact on the solid‐state physics world in the last decade not only achieving great success in photovoltaics but, more recently, also in the implementation of other optoelectronic devices. One of the main obstacles for the adoption of Pb‐based perovskite technologies are the high amounts of Pb needed in the conventional...
Despite the youthfulness of hybrid halide perovskite solar cells, their efficiencies are currently comparable to commercial silicon and have surpassed quantum‐dots solar cells. Yet, the scalability of these devices is a challenge due to their low reproducibility and stability under environmental conditions. However, the techniques reported to date...
Perovskite solar cells (PSCs) have reached impressively high efficiencies in a short period of time; however, the optoelectronic properties of halide perovskites are surprisingly complex owing to the coupled ionic-electronic charge carrier dynamics. Electrical impedance spectroscopy (EIS) is a widely used characterization tool to elucidate the mech...
Despite the youthfulness of hybrid halide perovskite solar cells, their efficiencies are currently comparable to commercial silicon and have surpassed quantum-dots solar cells. Yet, the scalability of these devices is a challenge due to their low reproducibility and stability under environmental conditions. However, the methods reported to date to...
We recently demonstrated that diaryl-naphthopyran photochromic dyes are efficient for sensitization of TiO2 mesoporous electrodes, thus allowing the fabrication of photo-chromo-voltaic cells that can self-adapt their absorption of light and their generation of electricity with the light intensity. Herein we report the synthesis, the characterisatio...
Recombination mechanisms in solar cells are frequently assessed through the determination of ideality factors. In this work we report an abrupt change of the value of the “apparent” ideality factor (nAP) in high‐efficiency FA0.71MA0.29PbI2.9Br0.1 based mesoscopic perovskite solar cells as a function of light intensity. This change is manifested as...
Polarizers are ubiquitous components in optoelectronic devices of daily use as displays, optical sensors or photographic cameras, among others. Yet the control over light polarization is an unresolved challenge as the main drawback of the current display technologies relays in significant optical losses. In such a context, organometal halide perovs...
Metal Halide Perovskites (MHPs) are mixed electronic–ionic semiconductors with an extraordinary complex optoelectronic behaviour and a record efficiency surpassing 25%. Interpreting small perturbation response of perovskite solar cells (PSCs) is significantly more challenging than for most other photovoltaics. This is for a variety of reasons, of w...
Impedance spectroscopy (IS) is a relatively straightforward experimental technique that is commonly used to obtain information about the physical and chemical characteristics of photovoltaic devices. However, the non-standard physical behaviour of perovskite solar cells (PSC), which are heavily influenced by the motion of mobile ion vacancies, has...
Metal Halide Perovskites (MHPs) are mixed electronic–ionic semiconductors with an extraordinary complex optoelectronic behaviour and a record efficiency surpassing 25%. Interpreting small perturbation response of perovskite solar cells (PSCs) is significantly more challenging than for most other photovoltaics. This is for a variety of reasons, of w...
Metal Halide Perovskites (MHPs) are mixed electronic–ionic semiconductors with an extraordinary complex optoelectronic behaviour and a record efficiency surpassing 25%. Interpreting small perturbation response of perovskite solar cells (PSCs) is significantly more challenging than for most other photovoltaics. This is for a variety of reasons, of w...
We compare the industrial viability of two emerging technologies for CO2 capture from flue gases, i.e., adsorption in porous commercial zeolites and biomass production by microalgae. Our study is organized in two steps: first, the best system is selected (either zeolite type or microalgae strain). Second, their performance is quantified and their a...
The photovoltaic field has undergone a rapid progress in the last decade due to the excellent optoelectronic properties of hybrid organic–inorganic metal halide perovskites. Perovskites were first introduced in the field as sensitizers in dye-sensitized solar cells with promising results but very poor stability because of the dissolution of perovsk...
Intensity Modulated Photocurrent Spectroscopy (IMPS) is a small-perturbation optoelectronic technique that measures the quantum efficiency of a photoelectrochemical device as a function of optical excitation frequency. Metal Halide Perovskites (MHPs) are mixed electronic–ionic semiconductors with an extraordinary complex optoelectronic behavior and...
Interpreting the impedance response of perovskite solar cells (PSCs) is significantly more challenging than for most other photovoltaics. This is for a variety of reasons, of which the most significant are the mixed ionic-electronic conduction properties of metal halide perovskites and the difficulty in fabricating stable, and reproducible, devices...
In this work we report a simple and cost‐effective CsPbBr 3 ‐based solar cell without ordinary selective contacts. To do so we follow an electrochemical approach consisting of three successive steps: (1) electrodeposition of PbO 2 directly on top of FTO substrates, (2) heterogeneous phase reaction with gaseous HBr and (3) spin‐coating of methanolic...
The Cover Feature illustrates the fabrication of a perovskite solar cell (PSC) based on lead fixation from an electrolyte as an electrodeposited PbO2 film, which is further converted to PbBr2 using gaseous HBr. Finally, PbBr2 is converted into CsPbBr3 using spin‐coated CsBr. A pressed carbon tip with a calibrated area was used to close the circuit...
Metal halide perovskites (MHPs) are nowadays one of the most studied semiconductors due to their exceptional performance as active layers in solar cells. Although MHPs are excellent solid-state semiconductors, they are also ionic compounds, where ion migration plays a decisive role in their formation, their photovoltaic performance and their long-t...
High efficiencies of over 20% have been reported in the literature for both planar and mesoscopic hybrid perovskite solar cells, and the preferred configuration for scale-up and commercialization is still a matter of debate. The mesoscopic configuration generally requires a high-temperature processing step, which limits applications and makes the p...
Metal halide perovskites (MHPs) are nowadays one of the most studied semiconductors due to their exceptional performance as active layers in solar cells. Although MHPs are excellent solid-state semiconductors, they are also ionic compounds, where ion migration plays a decisive role in their formation, their photovoltaic performance and their long-t...
Interpreting the impedance response of perovskite solar cells (PSC) is significantly more challenging than for most other photovoltaics. This is for a variety of reasons, of which the most significant are the mixed ionic-electronic conduction properties of metal halide perovskites and the difficulty in fabricating stable, and reproducible, devices....
In article number 1901524, Angel Barranco, Juan R. Sanchez‐Valencia, and co‐workers develop a simple approach to fabricate dopant‐free Spiro‐OMeTAD [2,2′,7,7′‐tetrakis (N,N‐di‐p‐methoxyphenyl‐amine)9,9′‐spirobifluorene] layers by vacuum sublimation. Temperature control of the samples during evaporation induces crystalline and microstructural change...
In this work, we report the unprecedented sublimation under vacuum conditions of the most widely used SSHC in perovskite solar cells, the Spiro‐OMeTAD, in the form of dopant‐free crystalline layers. In addition, we demonstrate the enhanced stability of these layers acting as SSHC in PSCs in comparison with the solution‐processed counterpart. Our re...
The main handicap still hindering the eventual exploitation of organometal halide perovskite‐based solar cells is their poor stability under prolonged illumination, ambient conditions, and increased temperatures. This article shows for the first time the vacuum processing of the most widely used solid‐state hole conductor (SSHC), i.e., the Spiro‐OM...
Deep eutectic solvents (DESs) are lately expanding their use to more demanding applications upon aqueous dilution thanks to the preservation of the most appealing properties of the original DESs while overcoming some of their most important drawbacks limiting their performance, like viscosity. Both experimental and theoretical works have studied th...
Remote plasma assisted vacuum deposition (RPAVD) is a very versatile methodology for the synthesis of functional films and multilayers for photonic, sensing, nanoelectronic and biomedical applications. Besides, the RPAVD methodology permits to deposit highly conformal multifunctional organic films to encapsulate fragile supported nanostructures wit...
The control over the precursor concentration is used to fabricate sensitized and thin-film perovskite solar cells. The dominating capacitance contributions in these devices reveal the main processes determining the response of perovskite solar cells, which enables the development of an impedance spectroscopy equivalent circuit for perovskite solar...
Fundamental working mechanisms of perovskite solar cells remain an elusive topic of research. Impedance spectroscopy (IS) has been key to characterize the main physical processes governing the behavior of dye and quantum dot sensitized solar cells, which are considered, in many aspects, predecessor technologies. In contrast, IS application to perov...
Metal halide perovskites are mixed electronic-ionic semiconductors with an extraordinary rich optoelectronic behavior and the capability to function very efficiently as active layers in solar cells, with a record efficiency surpassing 23% nowadays. In this letter we carry out an impedance spectroscopy analysis of two perovskite solar cells with qui...
Although perovskite solar cells have demonstrated impressive efficiencies in research labs (above 23%), there is a need of experimental procedures that allow their fabrication at ambient conditions, which would decrease substantially manufacturing costs. However, under ambient conditions, a delicate control of the moisture level in the atmosphere h...
Herein, the preparation of 1D TiO2 nanocolumnar films grown by plasma‐enhanced chemical vapor deposition is reported as the electron selective layer (ESL) for perovskite solar devices. The impact of the ESL architecture (1D and 3D morphologies) and the nanocrystalline phase (anatase and amorphous) is analyzed. For anatase structures, similar power...
In this work we exposed, for certain periods of time, devices of both architectures to light and/or humidity under open-circuit conditions. We found a better retention of the photovoltaic parameters for perovskite solar cells containing a mesoporous TiO2 layer, with a T50 value more than double that of planar devices. We compare the performance of...
We study the adsorption performance of metal-organic frameworks (MOFs) impregnated of ionic liquids (ILs). To this aim we calculated adsorption and diffusion of light gases (CO2, CH4, N2) and their mixtures in hybrid composites using molecular simulations. The hybrid composites consist of 1-ethyl-3-methylimidazolium thiocyanate impregnated in IRMOF...
In recent years, organo-halide perovskite solar cells have garnered a surge of interest due to their high performance and low-cost fabrication processing. Owing to the multilayer architecture of perovskite solar cells, interface not only has a pivotal role to play in performance, but also influences long-term stability. Here we have employed divers...
Perovskite solar cells are known to show very long response timescales, in the order of milliseconds to seconds. This generates considerable doubt over the validity of the measured external quantum efficiency and consequently the estimation of the short circuit current density. We observe a variation as high as 10% in the values of the EQE of perov...
Among many other applications, room-temperature ionic liquids (ILs) are used as electrolytes for storage and energy-conversion devices. In this work, we investigate, at the microscopic level, the structural and dynamical properties of 1-methyl-1-butyl-pyrrolidinium bis(trifluoromethanesulfonyl) imide [C4 PYR]+ [Tf2 N]- IL-based electrolytes for met...
A compromise between high power conversion efficiency and long-term stability of hybrid organic-inorganic metal halide perovskite solar cells is necessary for their outdoor photovoltaic application and commercialization. Herein, a method to improve the stability of perovskite solar cells under water and moisture exposure consisting in the encapsula...
Rapid degradation in humid environments is a major drawback of methylammonium lead iodide (CH3NH3PbI3), which is the archetypical component of perovskite solar cells. In this work, we have investigated the aging and degradation kinetics of CH3NH3PbI3 films and devices fabricated under controlled conditions as a function of relative humidity (RH), a...
This paper addresses the fabrication of vertically aligned [email protected]2 multishell nanotubes by a combined full vacuum-plasma approach at mild temperatures. The growth is carried out within the premises of a one-reactor approach, i.e. minimizing the number of vacuum chambers and sample transferences. In this way, the interface between ZnO and...