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Hot-substrate deposition of all-inorganic perovskite films for low-temperature processed high-efficiency solar cells
摘要： All-inorganic cesium lead halide perovskites (CsPbX3) have emerged as one of the most promising photovoltaic materials due to their superior thermal stability. However, the high phase transition temperatures (typically over 250 ?C) of CsPbX3 perovskites are incompatible with flexible substrates. Herein, we employed a simple hot-casting method to fabricate low-temperature processed CsPbI2Br films. By casting the perovskite precursor solution onto a hot substrate (maintained at 55 ?C), compact, large-grain and pinhole-free CsPbI2Br films can be prepared at a low post-annealing temperature, which outperform the conventional room temperature (RT)-casting and high-temperature (post-annealing at 340 ?C) processed CsPbI2Br films containing some voids. As a result, the hot-casting and low-temperature (post-annealing at 120 ?C) processed CsPbI2Br perovskite solar cells (PSCs) exhibited an outstanding power conversion efficiency (PCE) of 12.5%, which is much higher than that (2.91%) of the RT-casting processed CsPbI2Br devices. Further optimization of the post-annealing temperature (optimized value: 180 ?C) yielded the best performance of 13.8% for hot-casting processed CsPbI2Br devices. This study gives an effective and facile strategy toward low-temperature processed all-inorganic perovskite films and high-performance PSCs.
关键词： hot-casting method,All-inorganic cesium lead halide perovskites,perovskite solar cells,low-temperature processed,CsPbI2Br
更新于2025-09-11 14:15:04
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Switching excitonic recombination and carrier trapping in cesium lead halide perovskites by air
摘要： All-inorganic cesium lead halide perovskites have been emerging as the promising semiconductor materials for next-generation optoelectronics. However, the fundamental question of how the environmental atmosphere affects their photophysical properties, which is closely related to the practical applications, remains elusive. Here, we report the dynamic switching between radiative exciton recombination and non-radiative carrier trapping in CsPbBr3 by controlling the atmospheric conditions. Specifically, we show that the photoluminescence (PL) intensity from the CsPbBr3 crystals can be boosted by ~ 60 times by changing the surrounding from vacuum to air. Based on the comprehensive optical characterization, near-ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) as well as density functional theory (DFT) calculations, we unravel that the physisorption of oxygen molecules, which repairs the trap states by passivating the PL-quenching bromine vacancies, is accountable for the enhanced PL in air. These results are helpful for better understanding the optical properties of all-inorganic perovskites.
关键词： trap states,bromine vacancies,oxygen physisorption,photoluminescence,all-inorganic cesium lead halide perovskites
更新于2025-09-09 09:28:46