A solution-processed all-perovskite memory with dual-band light response and tri-mode operation

Integrating multiple semiconductors with distinct physical properties is a practical design strategy for realizing novel optoelectronic devices with unprecedented functionalities. In this work, a photonic resistive switching (RS) memory is demonstrated based on solution-processed bilayers of strontium titanate (SrTiO₃ or STO) quantum dots (QDs) and all-inorganic halide perovskite CsPbBr₃ (CPB) with an Ag/STO/CPB/Au architecture. Compared with the single-layer STO or CPB RS device, the double-layer device shows considerably improved RS performance with a high switching ratio over 10⁵, an endurance of 3000 cycles, and a retention time longer than 2 × 10⁴ s. The formation of heterojunction between STO and CPB significantly enhances the high resistance state, and the separation of the active silver electrode and the CPB layer contributes to the long-term stability. More importantly, the photonic RS device exhibits UV–visible dual-band response due to the photogating effect and the light-induced modification of the heterojunction barrier. Last, tri-mode operation, i.e., photodetector, memory, and photomemory, is demonstrated via tailoring the light and electric stimuli. This bilayer device architecture provides a unique approach toward enhancing the performance of photoresponsive data-storage devices.