Self‐Organized Superlattice and Phase Coexistence inside Thin Film Organometal Halide Perovskite

Organometal halide perovskites have attracted widespread attention as the most favorable prospective material for photovoltaic technology because of their high photoinduced charge separation and carrier transport performance. However, the microstructural aspects within the organometal halide perovskite are still unknown, even though it belongs to a crystal system. Here direct observation of the microstructure of the thin film organometal halide perovskite using transmission electron microscopy is reported. Unlike previous reports claiming each phase of the organometal halide perovskite solely exists at a given temperature range, it is identified that the tetragonal and cubic phases coexist at room temperature, and it is confirmed that superlattices composed of a mixture of tetragonal and cubic phases are self‐organized without a compositional change. The organometal halide perovskite self‐adjusts the configuration of phases and automatically organizes a buffer layer at boundaries by introducing a superlattice. This report shows the fundamental crystallographic information for the organometal halide perovskite and demonstrates new possibilities as promising materials for various applications.     

钙钛矿相有机金属卤化物太阳电池研究进展与展望

钙钛矿相有机金属卤化物太阳电池是以钙钛矿相有机金属卤化物作为吸光材料的薄膜太阳电池,因制备工艺简单、成本低廉、能量回报周期短以及光电转换效率高等优点而备受科学家的青睐。在钙钛矿相有机金属卤化物太阳电池研究发展的短短5年时间内,其光电转换效率已从最初的3.8%迅速上升到20%以上,超过了非晶硅、染料敏化、有机太阳电池等新一代薄膜电池历经10多年研究的成果。为了进一步提升效率,以期获得实际应用,钙钛矿相有机金属卤化物太阳电池的工作机制、新材料、温和制备工艺和稳定性是研究者们最为关注的研究方向。解决这些问题,对钙钛矿相有机金属卤化物太阳电池今后的发展起着指导和借鉴作用。介绍了钙钛矿相有机金属卤化物太阳电池的结构及其工作原理,对国内外钙钛矿相有机金属卤化物太阳电池的研究进行了总结和分析,指出了目前钙钛矿相有机金属卤化物太阳电池研究的不足,并对其未来的研究提出了一些建议。     

“Unleaded” Perovskites: Status Quo and Future Prospects of Tin‐Based Perovskite Solar Cells

The tremendous interest focused on organic–inorganic halide perovskites since 2012 derives from their unique optical and electrical properties, which make them excellent photovoltaic materials. Pb‐based halide perovskite solar cells, in particular, currently stand at a record efficiency of ≈23%, fulfilling their potential toward commercialization. However, because of the toxicity concerns of Pb‐based perovskite solar cells, their market prospects are hindered. In principle, Pb can be replaced with other less‐toxic, environmentally benign metals. Sn‐based perovskites are thus the far most promising alternative due to their very similar and perhaps even superior semiconductor characteristics. After years of effort invested in Sn‐based halide perovskites, sufficient breakthroughs have finally been achieved that make them the next runners up to the Pb halide perovskites. To help the reader better understand the nature of Sn‐based halide perovskites, their optical and electrical properties are systematically discussed. Recent progress in Sn‐based perovskite solar cells, focusing mainly on film fabrication methods and different device architectures, and highlighting roadblocks to progress and opportunities for future work are reviewed. Finally, a brief overview of mixed Sn/Pb‐based systems with their anomalous yet beneficial optical trends are discussed. The current challenges and a future outlook for Sn‐based perovskites are discussed.