A Quasi-Two-Dimensional Trilayered CsPbBr -based Dion-Jacobson Hybrid Perovskite toward High-Performance Photodetection.

Quasi-two-dimensional (Q-2D) Dion-Jacobson (DJ) organic-inorganic hybrid perovskites based on CsPbBr are promising candidates for photodetection. Previous studies have predicted that the photoresponse of such materials with high inorganic-layer numbers (n) will be more protruding in this portfolio. However, until now, only bilayered (n=2) CsPbBr -based DJ-type hybrid perovskites are obtained and the higher number of layers (n>2) remain completely unexplored, owing to the relatively high formation energies. Here, by incorporating diamine into the 3D CsPbBr motif, a new Q-2D trilayered CsPbBr -based DJ-type hybrid perovskite that contains organic cation and inorganic Cs metal, namely (4-AMP)Cs Pb Br (1, 4-AMP =4-(aminomethyl)piperidinium, n=3), is obtained. Excitingly, 1 exhibits excellent photoresponse, superior to its single-layered and bilayered counterparts. The resulting photodetectors thus exhibit a large on/off ratio (>10 ), high photodetectivity (6.5×10  Jones) and fast response speed (193 μs). As far as we know, 1 is the first Q-2D CsPbBr -based DJ-type hybrid perovskites with high n numbers. Our results may widen the range of the potential material in application of photodetection and will be helpful to design hybrid perovskites for other advanced optoelectronic devices.