A 2D-2D Ti3CN@BiOCl heterojunction and its application in photodetection

Bismuth oxychloride (BiOCl) has been prevalently applied in UV-photodetection due to its wide band gap. However, further application is hindered by its low light utilization efficiency and fast carrier recombination. In this work, a 2D-2D Ti3CN@BiOCl heterojunction was constructed to broaden the light absorption and increase the carrier mobility. A small amount of hole scavengers was utilized to suppress the carrier recombination. According to DFT calculations, the electron transfer occurs from MXene to BiOCl and is subsequently converted into an electrical signal. The photo-response performance of Ti3CN@BiOCl was systematically investigated, where an optimized photocurrent density as high as 47.17 µA∙cm− 2 and a photoresponsivity of 12.50 mA/W could be achieved. Furthermore, Ti3CN@BiOCl was found to exhibit a broad-band and fast response (~ 0.04 s), and excellent long-term stability (~ 0.005% decrement for each cycle). This work highlights promising prospects of Ti3CN@BiOCl heterojunctions for use in photodetection, which also hold great potential for other types of optoelectronic devices.