Synthesis and Characterization of Mixed-Halide Inorganic-Organic Hybrid CH3NH3PbBr2.5Cl0.5 Perovskite for Photodetector Application

Inorganic-organic hybrid perovskite (ABX(3), A = organic cation, B = metal ion, X = halogen anion) combines the advantages of inorganic and organic materials. However, the properties and performance of mixed-halide CH3NH3PbBr2.5Cl0.5 (MAPbBr(2.)(5)Cl(0)(.5)) are still poorly understood. In this study, we synthetized MAPbBr(2.)(5)Cl(0)(.5) single crystal and studied its structure, optical, thermal stability properties and optoelectronics applications for photodetector device. Compared with those of MAPbCI(3), the interplanar distance of (100) crystal plane for MAPbBr(2.)(5)Cl(0)(.5) becomes larger and the absorption spectrum of MAPbBr(2.)(5)Cl(0)(.5) is extended to the visible region. The band gap of the MAPbBr(2.)(5)Cl(0)(.5) single crystal is 2.28 eV. We find the device based on MAPbBr(2.)(5)Cl(0)(.5) has high selectivity from 369 to 564 nm. The maximum Delta J (J(on) - J(off)) under 3.0 V bias voltage is about 1.2 mu A cm(-2) at 454 nm visible light with 1 W m(-2) light intensity (1/1000 of the standard sunlight intensity), which proves the device has a high sensitivity. The linear relationship is established between the value of Delta J and light intensity and bias voltage. The fast current intensity transients (Fit) shows that the disappearance period of photocurrent density is 0.3 ms, which indicates the device is rapidly responsive photodetector. The highest value (1.7%) of external quantum efficiency (EQE) and the highest value of detectivities (D) both appear at 480 nm visible light at 4.0 V bias voltage when the irradiation power is 30 W m(-2). Therefore, this simple and low-cost photoresponsive device is promising for industrial production of photodetector and photocatalysts device in the future.