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Improving the performance of ultra-flexible perovskite photodetectors through cation engineering
摘要： High performance ultra-flexible lightweight perovskite photodetectors hold promising applications on arbitrary substrates include unmanned aerial vehicles. Herein, we report a facile method to improve the performances of perovskite photodetectors on flexible ultrathin (50 μm) polyimide substrates by tuning the composition with different ratios of cations. In the presence of lead thiocyanate, a certain amount of formamidinium introduction could sufficiently enhance the methylammonium lead triiodide perovskite film quality with prolonged carrier lifetime. Perovskite photodetector with response time of ton=89 ms and toff=47 ms is achieved with a very simple device architecture. In addition, our flexible photodetectors maintain good performances after rigorous folding and bending, demonstrating excellent mechanical properties, which can be very useful for a variety of applications.
关键词： compositional engineering,mechanical stability,ultra-flexible detectors,perovskite photodetectors
更新于2025-09-23 15:19:57
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Thermodynamics of Multicomponent Perovskites: A Guide to Highly Efficient and Stable Solar Cell Materials
摘要： With their dramatic improvement of photoconversion efficiency, metal-halide perovskite (MHP) solar cells are receiving great attention. For successful deployment of these materials as next-generation solar cells, many research efforts are being undertaken to develop highly efficient and stable perovskite solar cells. Because compositional engineering in particular has provided a powerful route to optimize the material properties, MHPs with high efficiency and stability often include a number of different components. In this study, using ab-initio thermodynamics for ternary mixtures at the A-site (FA, MA, and Cs) and varying Br/I content at the X-site, we provide thermodynamic modeling on how mixtures of different cations and halides at A- and X-sites can modify the stability of MHPs. Our in-depth calculation reveals that Br mixing is inevitable to stabilize the corner-shared perovskite structure of highly efficient FAPbI3 with low bandgap. To maintain the minimal content of Br, which widens the bandgap, MA co-mixing is required, while Cs mixing contributes to prevent the decomposition of MHPs into precursors. We anticipate that the present study will provide thermodynamic insight into the distinctive roles of different components of MHPs and offer a design guideline for future compositional engineering of MHPs.
关键词： efficiency,thermodynamics,metal-halide perovskite,compositional engineering,stability,solar cells
更新于2025-09-23 15:19:57
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Improvement of the stability of perovskite solar cells in terms of humidity/heat via compositional engineering
摘要： Compositional engineering is one of the ways of controlling the phase structure and improving the stability of perovskite solar cells. This study is the investigation of how adding cesium (Cs) to Formamidium Lead Iodide (FAPbI3) perovskite affects the structure, morphology, performance and stability of hole-transport-free (HTF) mesoporous solar cells. It was shown that this addition leads to decrease in the lattice constant and the tolerance factor and causes perovskite band gaps to vary. The X-ray diffraction analysis also showed the removal of the non-photovoltaic perovskite phase and the conversion of the trigonal black phase to tetragonal structure. As 15% of Cs was added, the average efficiency of 7.41% and the highest efficiency of 11.78% were achieved for the HTF solar cells. Finally, FA0.85 Cs0.15PbI3 perovskite cells proved to be more stable than FAPbI3 reference cells at 150°C and the humidity of 90%.
关键词： Phase structure,Stability,Compositional engineering,Perovskite solar cells
更新于2025-09-23 15:19:57
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Morphology control of perovskite in green antisolvent system for MAPbI3-based solar cells with over 20% efficiency
摘要： Solvent engineering has been considered a reliable process for the fabrication of pinhole-free and highly crystalline perovskite thin films. Recently, green solvents have received immense attention, as the toxic antisolvents used in the conventional fabrication process cause environmental and health hazards. In this regard, ethyl acetate (EA) is a promising environmentally friendly antisolvent. Here, we present the fabrication of perovskites with controlled morphologies by changing the composition of the perovskite and the volume of EA in ambient humidity. The incorporation of [HC(NH2)2]PbIBr2 into a CH3NH3PbI3 matrix results in a grain size up to ~1.5 μm. This induces a considerable reduction of trap density, leading to the suppression of charge recombination and, consequently, improvement in the photoluminescence characteristics. The resulting power conversion efficiencies (PCEs) of the optimized devices are 20.93% and 19.51% for active areas of 0.12 cm2 and 0.7 cm2, respectively. The reduced diffusion of moisture along grain boundaries improves device stability. Further, by virtue of the excellent humidity resistance of EA, the film morphologies obtained at high relative humidity (50%) are similar to those obtained under dry conditions, exhibiting an impressive PCE of 20.11%. We believe that our optimized fabrication process using EA can be extended to other green antisolvent systems.
关键词： Green antisolvent,Ethyl acetate,Grain size,Solvent and compositional engineering,Perovskite solar cell
更新于2025-09-16 10:30:52
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Highly crystalline CsPbI <sub/>2</sub> Br films for efficient perovskite solar cells <i>via</i> compositional engineering
摘要： All-inorganic CsPbI2Br shows high thermal stability for promising application in perovskite solar cells (PSCs). The performance of PSCs is significantly affected by their morphology and crystallinity induced by compositional ratio, solvent/anti-solvent engineering and post thermal annealing. In this study, the compositional ratio effect of two precursors, PbI2 and CsBr, on the power conversion efficiency (PCE) of a device with ITO/SnO2/CsPbI2Br/Spiro-MeOTAD/Au structure was investigated. With the assistance of anti-solvent chlorobenzene, perovskite with a PbI2 : CsBr ratio of 1.05 : 1 showed a high quality thin film with higher crystallinity and larger grain size. In addition, the molar ratio of precursors PbI2 and CsBr improved the PCE of the PSCs, and the PSCs fabricated using the perovskite with an optimal ratio of PbI2 and CsBr exhibited a PCE of 13.34%.
关键词： compositional engineering,CsPbI2Br,perovskite solar cells,thermal stability,power conversion efficiency
更新于2025-09-12 10:27:22