Publications by authors named "Seungchan Ryu"

Physical neural networks made of analog resistive switching processors are promising platforms for analog computing. State-of-the-art resistive switches rely on either conductive filament formation or phase change. These processes suffer from poor reproducibility or high energy consumption, respectively.

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The band gap of formamidinium lead iodide (FAPbI3) perovskites allows broader absorption of the solar spectrum relative to conventional methylammonium lead iodide (MAPbI3). Because the optoelectronic properties of perovskite films are closely related to film quality, deposition of dense and uniform films is crucial for fabricating high-performance perovskite solar cells (PSCs). We report an approach for depositing high-quality FAPbI3 films, involving FAPbI3 crystallization by the direct intramolecular exchange of dimethylsulfoxide (DMSO) molecules intercalated in PbI2 with formamidinium iodide.

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Of the many materials and methodologies aimed at producing low-cost, efficient photovoltaic cells, inorganic-organic lead halide perovskite materials appear particularly promising for next-generation solar devices owing to their high power conversion efficiency. The highest efficiencies reported for perovskite solar cells so far have been obtained mainly with methylammonium lead halide materials. Here we combine the promising-owing to its comparatively narrow bandgap-but relatively unstable formamidinium lead iodide (FAPbI3) with methylammonium lead bromide (MAPbBr3) as the light-harvesting unit in a bilayer solar-cell architecture.

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Organolead trihalide perovskite materials have been successfully used as light absorbers in efficient photovoltaic cells. Two different cell structures, based on mesoscopic metal oxides and planar heterojunctions have already demonstrated very impressive advances in performance. Here, we report a bilayer architecture comprising the key features of mesoscopic and planar structures obtained by a fully solution-based process.

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Unlabelled: We report on the fabrication of PbS/CH3NH3PbI3 (=MAP) core/shell quantum dot (QD)-sensitized inorganic-organic heterojunction solar cells on top of mesoporous (mp) TiO2 electrodes with hole transporting polymers (P3HT and

Pedot: PSS). The PbS/MAP core/shell QDs were in situ-deposited by a modified successive ionic layer adsorption and reaction (SILAR) process using PbI2 and Na2S solutions with repeated spin-coating and subsequent dipping into CH3NH3I (=MAI) solution in the final stage. The resulting device showed much higher efficiency as compared to PbS QD-sensitized solar cells without a MAP shell layer, reaching an overall efficiency of 3.

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