Enhanced Weak-Light Detection of Perovskite Photodetectors through Perovskite/Hole-Transport Material Interface Treatment

Enhancement in weak-light detection and other photodetection properties was observed for organic–inorganic halide perovskite photodetectors as a result of benzylammonium iodide (BzAI) treatment at the methylammonium lead triiodide (MAPbI₃) and hole-transport layer (HTL) interface. After treatment, growth of the two-dimensional Ruddlesden–Popper perovskite phase was observed at the MAPbI₃ surface, which shifted the overall surface work function upwards and thus effectively facilitated charge transfer across the MAPbI₃/HTL interface. As a result, the fully fabricated device with 10 mg/mL (BzAI/isopropanol) treatment exhibited shorter rise time (t_rise) and decay time (t_decay) of 53 and 38 μs, respectively, compared to t_rise and t_decay of 214 and 120 μs, respectively, for the pristine MAPbI₃ sample. In addition, the BzAI-treated device exhibited larger linearity compared to the pristine MAPbI₃ sample, demonstrating a high and stable specific detectivity of 1.49 × 10¹³ to 2.14 × 10¹³ Jones under incident light intensity of 10^–3 to 10⁰ mW/cm², respectively.