Perovskite Photodetectors based on CH₃ NH₃ PbI₃ Single Crystals

As very important light-harvesting materials, organic-inorganic perovskites have showed an alluring prospect in optoelectronic devices. However, most of the perovskite devices, such as photodetectors reported recently, are based on the polycrystalline films of perovskites, and the large grain boundaries and amounts of defects existing in films are unfavorable for the further improvement of device performance. Herein, high-quality single crystals of CH₃ NH₃ PbI₃ were successfully prepared through a simple solution immersing method. The obtained CH₃ NH₃ PbI₃ crystals showed the morphologies of nanowires and nanoplates, which were confirmed to belong to the same tetragonal phase. Both nanowire- and nanoplate-based photodetectors exhibited improved performance over CH₃ NH₃ PbI₃ polycrystalline thin films, with an on/off ratio approaching 10³ , which is one of the highest values reported so far for perovskite photodetectors.