Perovskite CH3NH3PbI3-xBrx Single Crystals with Charge-Carrier Lifetimes Exceeding 260 μs.

The long carrier lifetimes in perovskite single crystals have drawn significant attention recently on account of their irreplaceable contribution to high-performance photovoltaic (PV) devices. Herein, the optical and optoelectronic properties of CH3NH3PbI3 and CH3NH3PbI3-xBrx (with five different contents of Br doped) single crystals were investigated. Notably, a superior carrier lifetime of up to 262 μs was observed in the CH3NH3PbI3-xBrx (I/Br = 10:1 in the precursor) single-crystal PV device under 1 sun illumination, which is two times longer than that in the CH3NH3PbI3 single crystal. Further study confirmed that the ultralong carrier lifetime was ascribed to the integrated superiority derived from both the low trap-state density and high charge-injection efficiency of the device interface. On this basis, appropriate incorporation of Br is useful in the design of better PV devices.