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Efficient, stable silicon tandem cells enabled by anion-engineered wide-bandgap perovskites
摘要： Maximizing the power conversion efficiency (PCE) of perovskite-silicon tandem solar cells that can exceed the Shockley-Queisser single-cell limit requires a high performing, stable perovskite top cell with a wide band gap. We developed a stable perovskite solar cell with a band gap of ~1.7 electron volt that retained over 80% of its initial PCE of 20.7% after 1000 hours of continuous illumination. Anion engineering of phenethylammonium (PEA)-based two-dimensional (2D) additives was critical for controlling the structural and electrical properties of 2D passivation layers based on a PbI2-framework. The high PCE of 26.7% of a monolithic two-terminal wide gap perovskite/Si tandem solar cell was made possible by the ideal combination of spectral responses of the top and bottom cells.
关键词： tandem solar cells,anion engineering,perovskite,silicon,wide-bandgap
更新于2025-09-23 15:21:01
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Anion Engineering Enhanced Response Speed and Tunable Spectral Responsivity in Gallium-Oxynitrides-Based Ultraviolet Photodetectors
摘要： Most of the currently developed Ga2O3-based solar blind photodetectors exhibit unexpected high persistent photoconductive gain at the expense of low response speed, and thus, the suppression of carrier trapping remains challenging. In this work, we demonstrated amorphous gallium-oxynitride-based (GaON) ultraviolet photodetectors with tunable spectral response and enhanced response speed by in situ anion engineering with a reactive sputtering technique. The tunable spectral response from 4.95 to 4.37 eV is a result of a bandgap narrowing effect, attributed to the elevation of the valence band maximum (VBM) by the hybridization of N 2p and O 2p states and the enhanced p-d repulsion. The constructed GaON PDs with a proper nitrogen composition exhibit remarkably reduced dark current and a fast response time of about 100 μs. Oxygen vacancies are deactivated by the lift-up of VBM so that slow carrier detrapping processes are suppressed, resulting in the reduced persistent photoconductivity and improved response speed. Meanwhile, nitrogen introduction increases the recombination and scattering probabilities of photoexcited carriers, which results in the reduced photoresponsivity. Thus, the rational design through anion engineering allows a flexibility in bandgap modulation and suppression of carrier trapping in oxynitrides, which provides an alternative strategy to achieve high-speed ultraviolet photodetectors.
关键词： ultraviolet photodetectors,gallium oxynitrides,bandgap modulation,photoconductive gain,anion engineering
更新于2025-09-23 15:19:57