MAPbI3 Single Crystals Free from Hole Trapping Centers for Enhanced Photodetectivity

Perovskite single crystals (PSCs) are considered the next breakthrough in optoelectronics research due to their free-grain boundary and much lower density of trap states compared to those of their polycrystalline counterparts. However, the inevitable formation of triiodide-based intrinsic defects during high-temperature crystal growth is one of the major challenges impeding the further development of optoelectronic devices based on PCSs. Here, we not only identified the existence of these triiodide ions as hole-trapping centers and their tremendous negative impact on the performance of PCSs, but more importantly, we used a reduction treatment to prevent their formation during crystal growth. The removal of such defect centers resulted in much higher charge carrier mobility and longer carrier lifetime than the untreated counterparts, leading to an exceptional photodetection properties. The I_3^--free MAPbI3 single crystal (MSC) devices consistently generated a more than 100 times higher photocurrent than t...