UV Photodetectors Based on BiOCl Nanosheet Arrays: The Effects of Morphologies and Electrode Configurations.

A facile chemical bath method is adopted to grow bismuth oxychloride (BiOCl) nanosheet arrays on a piece of Cu foil (denoted as BiOCl-Cu) and isolated BiOCl nanosheets are collected by ultrasonication. A self-supporting BiOCl film is obtained by the removal of Cu foil. Photodetectors (PDs) based on these BiOCl materials are assembled and the effects of morphologies and electrode configurations on the photoelectric performance of these PDs are examined. The BiOCl nanosheet PD achieves high responsivities in the spectral range from 250 to 350 nm, while it presents quite a small photocurrent and slow response speed. The BiOCl film PD yields low photocurrents and near-unity on-off ratios, demonstrating poor photoelectric performance. The photocurrent of the BiOCl-Cu PD with both electrodes on the BiOCl film is much higher than those of these above-mentioned PDs, and the response times are fast. Meanwhile, the BiOCl-Cu PD with separate electrodes on the BiOCl film and Cu foil achieves even higher photocurrents and presents a self-powering characteristic, depicting the improved photodetecting performances induced by the specific morphology and distinct electrode configuration. These results would promote the applications of BiOCl nanostructures in the photoelectric devices.