Phenethylammonium iodide modulated SnO2 electron selective layer for high performance, self-powered metal halide perovskite photodetector

[Display omitted] •PEAI passivates SnO2 film interface defects and improves electron selective layer carrier mobility and conductivity.•The NO bond formed by SnO2 and ammonia functional groups of PEAI is beneficial for electron extraction and transport between the perovskite and the electron selective layer.•Improved environmental stability of perovskite photodetectors due to the reduction of surface hydroxyl groups after PEAI modification.•Obtained a higher specific detectivity of 2.57 × 1012 Jones and a responsivity of 0.40 A/W in self-powered mode. A tailored interface located at the buried perovskite heterojunction is often employed to ameliorate the performance and reliability of n-i-p plane structure perovskite photovoltaic devices. Refinements of interfacial properties such as energy band alignment, surface defects passivation and lattice matching ensure efficient extraction and transport of photogenerated charge carriers. Here, we demonstrated that the phenethylammonium iodide (PEAI) is employed to regulate the tin oxide (SnO2)/perovskite interface. Incorporating PEAI into SnO2 can passivate crystallographic defects and realign the energy band, thereby contributing to high electronic mobility of electron selective layers (ESLs) and electron extraction rate optimization at the buried perovskite heterojunction interface. Additionally, the charge carrier non-radiative recombination of perovskites based on PEAI- modified SnO2 is also suppressed due to the augmentation of perovskite crystallinity induced by the hydrophobicity of the ESL film. Meanwhile, theoretical calculations verified the intrinsic mechanism that the formed N-O bond interaction facilitates charge transfer at the SnO2/perovskite interface. Consequently, metal halide perovskite photodetector (PPD) based on PEAI-modified SnO2 achieved a decent specific detectivity of 2.57 × 1012 Jones (1 Jones = 1 cm Hz1/2 W−1), a responsivity of 0.40 A/W and an extensive linear dynamic range of 161 dB with self-powered mode. The unencapsulated PPD with PEAI-modified SnO2 ESL maintains over 75% of the initial photoresponse after 30 days in the atmospheric environment.