Van der Waals Epitaxial Deposition of CsPbBr₃ Films for Flexible Optoelectronic Applications

Growth of high-quality inorganic halide perovskite films has attracted increasing attention in recent years for their important applications in solar cells, photodetectors, and communications. In this study, a centimeter-sized inorganic perovskite film of CsPbBr3 was prepared on an atomically flat flexible muscovite substrate by using pulsed laser deposition. Van der Waals epitaxial growth of pure cubic phase CsPbBr3 film is achieved by optimizing deposition conditions. In order to explore its potential in optoelectronic applications, the CsPbBr3 perovskite film was assembled into a planar photodetector. Benefitting from the high crystallinity of the film, the photodetector demonstrates an ultralow dark current and a high sensitivity to light. Under 10 V bias voltage and 405 nm irradiation, the device presents a high photocurrent on/off ratio of 1.1 × 105, a specific detectivity of 2.41 × 1014 Jones, and an ultrafast response time (the rising and decaying times are 42.16 μs and 44.88 μs, respectively). Moreover, the CsPbBr3-based photodetectors without encapsulation show good long-term stability (30 days with 6% attenuation) and bending stability. All these results indicate that a CsPbBr3 film epitaxially grown on flexible muscovite is a promising candidate for flexible optoelectronic applications.