UV–Vis photodetector based on ionic liquid-modified perovskite–ZnO composite

Photodetectors (PDs) that combine inorganic semiconductors with organic lead halide perovskites to produce broader spectral responses have captured great interest from researchers; however, the imperfect perovskite crystallinity and the defects on the film surface are still the main factors inhibiting the PD's capability. Here, we proposed a simple method by introducing ionic liquid [1-butyl-3-methylimidazolium iodide (BMII)] into ZnO/CH3NH3PbI3 to encourage the growth of perovskite grains, raise the crystallinity of perovskite, and reduce the trap states, finally enhancing the photoelectric performances. After the addition of BMII, there are 171-fold, 74-fold, and 76-fold increases, respectively, in the light–dark current ratio, the spectral responsivity, and the external quantum efficiency, meanwhile, detectivity can reach 2.58 × 1013 Jones in the UV–vis range. The impressive results can be owed to the higher carrier concentration of ZnO/CH3NH3PbI3 with BMII, which can facilitate the charge transfer and suppress the recombination of photogenerated carriers. This study may be of assistance to extend our knowledge of developing high-performance PDs.