Universal Strategy for Improving Perovskite Photodiode Performance: Interfacial Built‐In Electric Field Manipulated by Unintentional Doping

Organic–inorganic halide perovskites have demonstrated significant light detection potential, with a performance comparable to that of commercially available photodetectors. In this study, a general design guideline, which is applicable to both inverted and regular structures, is proposed for high‐performance perovskite photodiodes through an interfacial built‐in electric field (E) for efficient carrier separation and transport. The interfacial E generated at the interface between the active and charge transport layers far from the incident light is critical for effective charge carrier collection. The interfacial E can be modulated by unintentional doping of the perovskite, whose doping type and density can be easily controlled by the post‐annealing time and temperature. Employing the proposed design guideline, the inverted and regular perovskite photodiodes exhibit the external quantum efficiency of 83.51% and 76.5% and responsivities of 0.37 and 0.34 A W(−1), respectively. In the self‐powered mode, the dark currents reach 7.95 × 10(−11) and 1.47 × 10(−8) A cm(−2), providing high detectivities of 7.34 × 10(13) and 4.96 × 10(12) Jones, for inverted and regular structures, respectively, and a long‐term stability of at least 1600 h. This optimization strategy is compatible with existing materials and device structures and hence leads to substantial potential applications in perovskite‐based optoelectronic devices.