Wafer-sized 2D perovskite single crystal thin films for UV photodetectors

Two-dimensional (2D) organic–inorganic hybrid perovskites are promising for next-generation optoelectronic materials due to their enhanced stability, controllable quantum well thickness and excellent photoelectric properties. The growth of large lateral size, small thickness and high-quality single crystal films is necessary for the practical application of devices. Herein, we report a gas–liquid interface crystalline route to grow BA2PbBr4 (BA = CH3CH2CH2CH2NH3+) single crystal films and achieve wafer size (38 cm2) and thinness as little as 78 nm (aspect ratio > 105). Moreover, an ultraviolet-photodetector of the single crystal thin film presents a dark current of ∼10−14 A, a detectivity of ∼1012 Jones and fast response time (τrise = 9.7 ms and τdecay = 8.8 ms). Our work provides a way to grow 2D perovskite single crystal films with large size and small thickness, which is significant for the development of perovskite-type high-performance optoelectronic devices.