Effect of halide-mixing on the switching behaviors of organic-inorganic hybrid perovskite memory.

Mixed halide perovskite materials are actively researched for solar cells with high efficiency. Their hysteresis which originates from the movement of defects make perovskite a candidate for resistive switching memory devices. We demonstrate the resistive switching device based on mixed-halide organic-inorganic hybrid perovskite CHNHPbIBr (x = 0, 1, 2, 3). Solvent engineering is used to deposit the homogeneous CHNHPbIBr layer on the indium-tin oxide-coated glass substrates. The memory device based on CHNHPbIBr exhibits write endurance and long retention, which indicate reproducible and reliable memory properties. According to the increase in Br contents in CHNHPbIBr the set electric field required to make the device from low resistance state to high resistance state decreases. This result is in accord with the theoretical calculation of migration barriers, that is the barrier to ionic migration in perovskites is found to be lower for Br (0.23 eV) than for I (0.29-0.30 eV). The resistive switching may be the result of halide vacancy defects and formation of conductive filaments under electric field in the mixed perovskite layer. It is observed that enhancement in operating voltage can be achieved by controlling the halide contents in the film.