High-performance photodetector based on semi-encompassed CH3NH3PbCl3-ZnO microwire heterojunction with alterable spectral response

Recently, heterojunctions consisting of hybrid organic-inorganic lead (Pb) halide perovskites and other semiconductors have drawn increasing attention for the potential application in photodetectors due to their exceptional performance. However, their performance is usually limited by the relatively low crystalline quality of perovskites, and the response spectra of the devices are difficult to adjust according to the practical requirement. Here, high quality CH3NH3PbCl3 micro-sized crystals have been successfully fabricated on one side of individual ZnO microwire to form heterojunction photodetector by a two-step crystallization method. The heterojunction device presents a low dark current (60 nA at -6 V) along with a rapid response speed (rise time of mu s and fall time of similar to 500 mu s). More interestingly, the modulation of the response spectra and the responsivity can be realized by operating the device under front or back illumination due to the self-filtering properties. Our findings provide a promising method for combining perovskites with other inorganic materials to form high-performance heterojunction photodetectors.