Self-powered, all-solution processed, trilayer heterojunction perovskite-based photodetectors

Heterostructures composed of nano-/micro-junctions, combining the excellent photon harvesting properties of nano-systems and the ultrafast carrier transfer of micro-systems, have a promising role in high-performance photodetectors. In this paper, a highly-sensitive trilayer self-powered perovskite-based photodetector ITO/ZnO (70 nm)/CdS (150 nm)/CsPbBr₃ (200 nm)/Au, in which the CdS nanorods (NRs) layer is sandwiched between a ZnO/CsPbBr₃ interface to reduce the interfacial charge carriers' recombination and the charge transport resistance, is presented. Due to the strong built-in potential and the internal driving electric-field, an ultra-high On/Off current ratio of 10⁶ with a responsivity of 86 mA W^-1 and a specific detectivity of 6.2 × 10¹¹ Jones was obtained at zero bias under 85 µW cm^-2 405 nm illumination and its rise/decay time at zero bias is 0.3/0.25 s. Therefore, the enhanced device performance strongly suggests the great potential of such a trilayer heterojunction device for use in high-performance perovskite photodetectors.