Simultaneously elevating the resistive switching level and ambient-air-stability of 3D perovskite (TAZ-H)PbBr-based memory device by encapsulating into polyvinylpyrrolidone.

The study about simultaneously enhancing the resistive switching level and ambient-air-stability of perovskite-based memorizers will promote its commercialization. Here, a new 3D perovskite (TAZ-H)PbBr (TAZ-H = protonated thiazole) has been fabricated as FTO/(TAZ-H)PbBr/Ag device, which only exhibits binary memory performance with the high tolerant temperature of 170 °C. After encapsulating by polyvinylpyrrolidone (PVP), the (TAZ-H)PbBr@PVP composite-based device can demonstrate ternary resistive switching behavior with considerable ON2/ON1/OFF ratio (10: 10:1) and high ternary yield (68 %). Specially, this device presents good ambient-air stability at RH 80 % and thermal tolerance of 100 °C. The binary resistive switching mechanism can be ascribed to the halogen ion migration induced by bromine defects in the (PbBr) framework. But the ternary resistive switching phenomenon in the (TAZ-H)PbBr@PVP-based device could be depicted as the carrier transport from filled traps of PVP to (PbBr) framework (ON1 state) and then carriers flowing in the re-arranged (TAZ-H) chain in 3D channels (ON2 state). The PVP treatment can not only modify the grain boundary defects, but also facilitate the transport of injected carriers to the perovskite films via Pb-O coordinated bonds and inhibition of order-disorder transformation. This facial strategy for implementing ternary perovskite-based memorizers with good ambient-air-stability is quite meaningful for high-density memory in harsh environments.