Papers by José David Perea
Advanced Functional Materials
Dumbbell‐shaped systems based on PAHs‐BODIPY‐triarylamine hybrids TM‐(01‐04) are designed as nove... more Dumbbell‐shaped systems based on PAHs‐BODIPY‐triarylamine hybrids TM‐(01‐04) are designed as novel and highly efficient hole‐transporting materials for usage in planar inverted perovskite solar cells. BODIPY is employed as a bridge between the PAH units, and the effects of the conjugated π‐system's covalent attachment and size are investigated. Fluorescence quenching, 3D fluorescence heat maps, and theoretical studies support energy transfer within the moieties. The systems are extremely resistant to UVC 254 nm germicidal light sources and present remarkable thermal stability at degradation temperatures exceeding 350 °C. Integrating these systems into perovskite solar cells results in outstanding power conversion efficiency (PCE), with TM‐02‐based devices exhibiting a PCE of 20.26%. The devices base on TM‐01, TM‐03, and TM‐04 achieve PCE values of 16.98%, 17.58%, and 18.80%, respectively. The long‐term stability of these devices is measured for 600 h, with initial efficiency ret...
2019 IEEE 46th Photovoltaic Specialists Conference (PVSC), 2019
Characterization, material parameter extraction and subsequent optimization of solar cell devices... more Characterization, material parameter extraction and subsequent optimization of solar cell devices is a highly time‑consuming and complex procedure. In this work, we propose a method for quick extraction of limiting material parameters in solar cell devices using a surrogate, physics-embedded, neural network model. This surrogate model, implemented by an autoencoder architecture trained with a physical numerical model, allows to quickly extract the device parameters of interest at a certain process condition by using only a small number of illumination dependent current-voltage (JV) measurements. Our surrogate model adequately links material parameters at a certain process condition to final device efficiency. The model provides physical insights about the location of the best performing and robust processing conditions in solar cell devices. We test our approach with GaAs and CH3NH3PbI3 (MAPbI) perovskite solar cells. The model allows to find a set of processing conditions that maximize the performance of both GaAs and MAPbI solar cells, and analogous processing conditions that minimize solar cell variability.
European Journal of STEM Education, 2021
As part of an unprecedented collaborative outreach effort, we implemented an innovative STEM outr... more As part of an unprecedented collaborative outreach effort, we implemented an innovative STEM outreach project, where more than 80 middle and high school students from different traditionally underrepresented school districts in Colombia-with no previous knowledge on material science or photovoltaics-created Last Generation Solar Cells (LGSCs) that were part of several suborbital spaceflight missions. As a result, the students were able to contrast visual and instrumental data obtained from the solar cells and modules that were launched to space with similar samples that remained on earth to measure the degradation that occurs during spaceflight conditions. At the same time, the students that participated were able to cultivate their curiosity, strengthen their scientific skills and increase their interest in pursuing careers in STEM fields. These experiences were possible thanks to an extraordinary collaborative network between public and private entities and the use of project-based education as a powerful driver of development, especially for low-to-middle-income countries, such as Colombia. Here, we share our methodology for constructing photovoltaic devices in rural settings, and we show the progression and impact of this novel scientific outreach project.
npj Computational Materials, 2020
An amendment to this paper has been published and can be accessed via a link at the top of the pa... more An amendment to this paper has been published and can be accessed via a link at the top of the paper.
Advanced Materials, 2020
Fundamental advances to increase the efficiency as well as stability of organic photovoltaics (OP... more Fundamental advances to increase the efficiency as well as stability of organic photovoltaics (OPVs) are achieved by designing ternary blends, which represents a clear trend toward multicomponent active layer blends. The development of high‐throughput and autonomous experimentation methods is reported for the effective optimization of multicomponent polymer blends for OPVs. A method for automated film formation enabling the fabrication of up to 6048 films per day is introduced. Equipping this automated experimentation platform with a Bayesian optimization, a self‐driving laboratory is constructed that autonomously evaluates measurements to design and execute the next experiments. To demonstrate the potential of these methods, a 4D parameter space of quaternary OPV blends is mapped and optimized for photostability. While with conventional approaches, roughly 100 mg of material would be necessary, the robot‐based platform can screen 2000 combinations with less than 10 mg, and machine‐...
Many organic electronics applications such as organic solar cells or thermoelectric generators re... more Many organic electronics applications such as organic solar cells or thermoelectric generators rely on PEDOT:PSS as a conductive polymer that is printable and transparent. It was found that doping PEDOT:PSS with sorbitol enhances the conductivity through morphological changes. However, the microscopic mechanism is not well understood. In this work, we combine computational tools with machine learning to investigate changes in morphological and electronic properties of PEDOT:PSS when doped with sorbitol. We find that sorbitol improves the alignment of PEDOT oligomers, leading to a reduction of energy disorder and an increase in electronic couplings between PEDOT chains. The high accuracy (r2 > 0.9) and speed up of energy level predictions of neural networks compared to density functional theory enables us to analyze HOMO energies of PEDOT oligomers as a function of time. We find a surprisingly low degree of static energy disorder compared to other organic semiconductors. This find...
npj Computational Materials, 2020
Process optimization of photovoltaic devices is a time-intensive, trial-and-error endeavor, which... more Process optimization of photovoltaic devices is a time-intensive, trial-and-error endeavor, which lacks full transparency of the underlying physics and relies on user-imposed constraints that may or may not lead to a global optimum. Herein, we demonstrate that embedding physics domain knowledge into a Bayesian network enables an optimization approach for gallium arsenide (GaAs) solar cells that identifies the root cause(s) of underperformance with layer-by-layer resolution and reveals alternative optimal process windows beyond traditional black-box optimization. Our Bayesian network approach links a key GaAs process variable (growth temperature) to material descriptors (bulk and interface properties, e.g., bulk lifetime, doping, and surface recombination) and device performance parameters (e.g., cell efficiency). For this purpose, we combine a Bayesian inference framework with a neural network surrogate device-physics model that is 100× faster than numerical solvers. With the traine...
Advanced Functional Materials, 2019
A multipurpose interconnection layer based on poly(3,4‐ethylenedioxythiophene) doped with poly(st... more A multipurpose interconnection layer based on poly(3,4‐ethylenedioxythiophene) doped with poly(styrene sulfonate) (PEDOT:PSS), and d‐sorbitol for monolithic perovskite/silicon tandem solar cells is introduced. The interconnection of independently processed silicon and perovskite subcells is a simple add‐on lamination step, alleviating common fabrication complexities of tandem devices. It is demonstrated experimentally and theoretically that PEDOT:PSS is an ideal building block for manipulating the mechanical and electrical functionality of the charge recombination layer by controlling the microstructure on the nano‐ and mesoscale. It is elucidated that the optimal functionality of the recombination layer relies on a gradient in the d‐sorbitol dopant distribution that modulates the orientation of PEDOT across the PEDOT:PSS film. Using this modified PEDOT:PSS composite, a monolithic two‐terminal perovskite/silicon tandem solar cell with a steady‐state efficiency of 21.0%, a fill facto...
Journal of the American Chemical Society, 2019
Effective, solution processable designs of interfacial electron transporting layers (ETLs) or hol... more Effective, solution processable designs of interfacial electron transporting layers (ETLs) or hole-blocking layers are promising tools in modern electronic devices, e.g. to improve performance, cost and stability of perovskite-based solar cells. Herein, we introduce a facile synthetic route of thiazole-modified carbon nitride with 1.5 nm thick nanosheets which can be processed to a homogeneous, metal-free ETL for inverted perovskite solar cells. We show that thiazole-modified carbon nitride enables electronic interface enhancement via suppression of charge recombination, achieving 1.09 V in V oc and a rise to 20.17 mA/cm 2 in J sc. Hence, this report presents the successful implementation of a carbon nitride-based structure to boost charge extraction from the perovskite absorber towards the electron transport layer in p-in devices. ASSOCIATED CONTENT Supporting Information. Experimental information, materials and characterization methods, elemental analysis, particle charge, PL, current density, SEM images and water contact angles.
Advanced Energy Materials, 2019
Ternary blends with broad spectral absorption have the potential to increase charge generation in... more Ternary blends with broad spectral absorption have the potential to increase charge generation in organic solar cells but feature additional complexity due to limited intermixing and electronic mismatch. Here, a model system comprising the polymers poly[5,5‐bis(2‐butyloctyl)‐(2,2‐bithiophene)‐4,4‐dicarboxylate‐alt‐5,5‐2,2‐bithiophene] (PDCBT) and PTB7‐Th and PC70BM as an electron accepting unit is presented. The power conversion efficiency (PCE) of the ternary system clearly surpasses the performance of either of the binary systems. The photophysics is governed by a fast energy transfer process from PDCBT to PTB7‐Th, followed by electron transfer at the PTB7‐Th:fullerene interface. The morphological motif in the ternary blend is characterized by polymer fibers. Based on a combination of photophysical analysis, GIWAXS measurements and calculation of the intermolecular parameter, the latter indicating a very favorable molecular affinity between PDCBT and PTB7‐Th, it is proposed that a...
Materials, 2019
We report here on the development of composite thick films exhibiting hybrid superconducting and ... more We report here on the development of composite thick films exhibiting hybrid superconducting and ferromagnetic properties, produced through a low-cost, fast, and versatile process. These films were made of high Tc cuprate superconductor Bi2Sr2(Ca,Y)2Cu3O10 (with Y:Ca ratio of 5%) and ferromagnetic perovskite La2/3Ba1/3MnO3, synthesized by melting-quenching annealing process on a MgO substrate. Curie temperature for La2/3Ba1/3MnO3 was determined (~336 K ) by magnetic field assisted thermogravimetric analysis (TGA), while superconducting behavior of Bi2Sr2(Ca,Y)2Cu3O10/MgO films was observed through temperature-dependent resistance measurements. Superconducting features in our hybrid compound were corroborated by temperature-dependent resistivity and magnetic susceptibility.
Macromolecules, 2017
Organic solar cells based on multinary components are promising to further boost the device perfo... more Organic solar cells based on multinary components are promising to further boost the device performance. The complex interplay of the morphology and functionality needs further investigations. Here, we report on a systematic study on the morphology evolution of prototype ternary systems upon adding sensitizers featuring similar chemical structures but dramatically different crystallinity, namely poly(3-hexylthiophene) (P3HT) and indene-C 60-bisadduct (ICBA) blends with poly[(4,4′-bis(2-ethylhexyl)dithieno[3,2-b:2′,3′-d]silole)-2,6-diyl-alt-(4,7-bis(2-thienyl)-2,1,3-benzothiadi-azole)-5,5′-diyl] (Si-PCPDTBT) and poly-[2,6-(4,4-bis(2-ethylhexyl)-4H-cyclopenta[2,1-b;3,4-b′]-dithiophene)-alt-4,7-(2,1,3-benzothiadiazole)] (C-PCPDTBT), employing energy-filtered transmission electron microscopy (EFTEM) and resonant soft X-ray scattering (RSoXS). In addition, a combined density functional theory (DFT) and artificial neuronal network (ANN) computational approach has been utilized to calculate the solubility parameters and Flory−Huggins intermolecular parameters to evaluate the influence of miscibility on the final morphology. Our experiments reveal that the domain spacing and purity of ICBA-rich domains are retained in Si-PCPDTBT-based systems but are strongly reduced in C-PCPDTBT-based ternary systems. The P3HT fiber structure are retained at low sensitizer content but dramatically reduced at high sensitizer content. The theoretical calculations reveal very similar miscibility/compatibility between the two sensitizers and ICBA as well as P3HT. Thus, we conclude that mainly the crystallization of Si-PCPDTBT drives the nanostructure evolution in the ternary systems, while this driving force is absent in C-PCPDTBT-based ternary blends.
ACS Applied Materials & Interfaces, 2017
A novel main-chain poly(fullerene) poly{(fullerene)-alt-[2,5-bis(octyloxy)terephthalaldehyde]} (P... more A novel main-chain poly(fullerene) poly{(fullerene)-alt-[2,5-bis(octyloxy)terephthalaldehyde]} (PPC4) is investigated for its hypothesized superior morphological stability as an electron accepting material in organic photovoltaics relative to the widely used fullerene phenyl-C61butyric acid methyl ester (PCBM). When mixed with poly(3-hexylthiophene-2,5-diyl) (P3HT) PPC4 affords low charge generation yields due to poor intermixing within the blend. The adoption of a multi-acceptor system, by introducing PCBM into the P3HT:poly(fullerene) blend, was found to lead to a threefold enhancement in charge generation, affording power conversion efficiencies very close to the prototypical P3HT:PCBM binary control. Upon thermal stressing, and in contrast to the P3HT:PCBM binary, photovoltaic devices based on the multi-acceptor system demonstrated significantly improved stability, outperforming the control due to the suppression of the PCBM migration and aggregation processes responsible for rapid device failure. We rationalize the influence of fullerene miscibility and its implications on device performance in terms of a thermodynamic model based on Flory-Huggins solution theory. Finally, the potential universal applicability of this approach for thermal stabilisation of organic solar cells is demonstrated utilizing an alternative low bandgap polymer donor system.
Journal of Materials Chemistry A, 2017
The miscibility has more influence than the crystallinity on the optimized acceptor : donor ratio... more The miscibility has more influence than the crystallinity on the optimized acceptor : donor ratio in solar cells.
Energy & Environmental Science, 2017
This work introduces nickel(ii) dibutyldithiocarbamate as a broadband and universal antioxidant f... more This work introduces nickel(ii) dibutyldithiocarbamate as a broadband and universal antioxidant for conjugated polymer semiconductors.
Journal of Materials Chemistry A, 2017
A complete regioisomer separation of indene-C60 bisadduct (IC60BA) for polymer solar cell (PSC) a... more A complete regioisomer separation of indene-C60 bisadduct (IC60BA) for polymer solar cell (PSC) applications was conducted for the first time.
The Journal of Physical Chemistry B, 2016
The solubility of organic semiconductors in environmentally benign solvents is an important prere... more The solubility of organic semiconductors in environmentally benign solvents is an important prerequisite for the widespread adoption of organic electronic appliances. Solubility can be determined by considering the cohesive forces in a liquid via Hansen solubility parameters (HSP). We report a numerical approach to determine the HSP
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Papers by José David Perea