Progress and perspective of perovskite thin single crystal photodetectors

Metal halide perovskites show immense promise in photodetection applications, having been employed in the research of photodiodes, photoconductors, and phototransistors. However, the majority of current photodetectors utilizing perovskite materials rely on polycrystalline thin films, and the presence of grain boundaries and defects hinders their photoelectric performance, creating a bottleneck in further advancements. To address this issue, researchers have employed techniques such as inverse temperature crystallization (ITC) and anti-solvent vapor-assisted crystallization (AVC) to synthesize various perovskite single crystals. Bulk single crystal perovskite structures are advantageous due to their lack of grain boundaries, resulting in lower dark current and noise in photodetectors, thereby enhancing their weak light detection capabilities. Additionally, the diminished presence of grain boundaries extends the lifetime of photo-generated carriers, providing a foundation for improved detector performance. However, due to the excellent optical absorption coefficient of perovskites, the excessive thickness of bulk single crystals can only increase the probability of carrier recombination, impacting the photodetector's performance. Consequently, perovskite thin single crystal materials prepared by controlling longitudinal size have garnered significant interest in novel detector research. Various techniques, such as space-confined method, surface tension-assisted method, and vapor phase epitaxy, have been proposed to growth thin single crystals with controllable thickness. These methods have been continually optimized to enhance crystal quality. Thin single crystal perovskites not only enhance photodetector performance but also hold potential for large-area single crystal production, supporting the development of photodetector imaging arrays. This paper outlines the fundamental principles behind perovskite single crystal growth, introduces various technological approaches developed for thin perovskite single crystal growth, and analyzes the resulting materials from different growth methods. It further reviews notable studies in the realm of perovskite thin single crystal photodetectors for different device types. Finally, the paper discusses current challenges and issues in this field while offering insights into potential future directions of development.