Tin‐Based 2D/3D Perovskite Vertical Heterojunction for High‐Performance Synaptic Phototransistors

Abstract There is considerable interest in photodetectors based on nontoxic lead‐free perovskites. Tin‐based perovskites have been regarded as one type of the most promising candidate materials for these devices due to their relatively low bandgap and high light absorption coefficient. In this work, a stacked 2D/3D heterostructure in perovskite films is achieved through a convenient vacuum drying process, which results in an ultrahigh responsivity of up to 6.8 × 10 5 A W −1 and a high detectivity up to 4.0 × 10 14 Jones at a low gate voltage of −5 V across a broad wavelength region from ultraviolet to near‐infrared. Remarkably, the device exhibits synaptic behavior, as demonstrated by its photocurrent response to both photonic and electric stimuli, which closely resembles the memory behavior observed in biological neural networks, promising applications in opto‐synaptic devices.