Improved self-powered perovskite CHNHPbI/SnO heterojunction photodetectors achieved by interfacial engineering with a synergic effect.

Lead halide perovskite heterojunctions have been considered as important building blocks for fabricating high-performance photodetectors (PDs). However, the interfacial defects induced non-radiative recombination and interfacial energy-level misalignment induced ineffective carrier transport severely limit the performance of photodetection of resulting devices. Herein, interfacial engineering with a spin-coating procedure has been studied to improve the photodetection performance of CHNHPbI/SnO heterojunction PDs, which were fabricated by sputtering a SnO thin film on ITO glass followed by spin-coating a CHNHPbI thin film. It has shown that spin-coating of a SnO layer on the sputtered SnO thin films suppressed the surface oxygen vacancies of SnO thin films and up-shifted their conduction band, which suppressed the interfacial non-radiative recombination and enhanced the carriers transport at the CHNHPbI/SnO interface, respectively. Accordingly, improved photodetection performance, such as the reduced dark current and increased photocurrent, has been observed in the CHNHPbI/SnO heterojunction PDs, where the responsivity and detectivity of 0.077 A W and 2.0 × 10 jones, respectively, at the zero bias have been demonstrated. These results show a simple way to suppress the interfacial non-radiative recombination and enhance the carrier transport at the interface to fabricate improved perovskite heterojunction PDs in the future.