The controllable growth of CsPb2Cl5 nanosheets and their application as a stable photodetector for ultraviolet

Abstract

CsPb2Cl5 nanosheets were grown on different substrates by a simple solution method using dilute hydrochloric acid and absolute ethanol as solvents. The effect of temperature on the nanosheet growth was investigated. It was turned out that lower temperature is beneficial to the formation of nucleation of nanosheets. The nanosheet size changed from 20 μm to 60 μm, and the thickness gradually decreased from 750 nm to 120 nm as the growth temperature increased. The nucleation rate and distribution caused by contact angle induced solute transport on different substrates were obtained. The CsPb2Cl5 nanosheets were confirmed to possess a large Stokes shift and broad emission spectrum in the PL and prolonged carrier lifetime in transient fluorescence lifetime measurements. An ultraviolet photodetector based on CsPb2Cl5 nanosheets was reported for the first time. An extremely low dark current (pA-level), large on–off ratio and a fast response time with a rise time of 17 ms and a decay time of 32 ms were obtained. The detector placed in air without any package for over 2100 h still maintains 85 % photocurrent of the initial value.