Ag+/Bi3+ doping induced band structure and optoelectronic properties changes in CsPbBr3 crystals

Controllable doping is extensively used in designing the electronic and optical properties of perovskite. Bi-doped CsPbBr3 crystal shows a significant redshift at the absorption edge. However, the increase of defect states caused by Bi3+ ions will degrade the optical and electrical properties of the crystal. In this work, we report a series of Ag+/Bi3+ co-doped CsPbBr3 crystals prepared via a Bridgman method. The introduction of Ag+ ions could prevent the change for Fermi level and reduce the concentration of defect states caused by Bi3+ doping. Ag+/Bi3+ co-doped CsPbBr3 crystals show high carrier mobility that compare with undoped CsPbBr3 crystals. The light doping of Ag+/Bi3+ could remarkably improve the detection performances of CsPbBr3 to UV and laser. The maximum photocurrent for Ag+/Bi3+ co-doped CsPbBr3 crystal is even 50 times higher compared with undoped CsPbBr3 crystal under 365 nm UV lamps. Our findings provide a new strategy for controlling doping to improve the photoelectric properties of perovskite.