Abstract: Blue photodetectors (PDs) are attracting great attention for various applications. Commercial blue PDs based on inorganic GaP or InGaN absorbers are limited by their expensive, complex, and high-temperature fabrication techniques. Organic absorber-based blue PDs still have much lower photodetecting properties than inorganic blue PDs. In this study, a high-performance self-powered blue PD is developed using methylammonium lead halide (MAPbX₃; X = I, Br, and Cl) perovskites based on the economic and facile solution process at low temperatures. Optimal composition is obtained through halide-composition engineering. Our best-performing device exhibits an average external quantum efficiency and an average detectivity of 42.7% and 8.65 × 10¹¹ Jones, respectively, within the blue region. The peak responsivity of the proposed PD is 0.174 A W^-1 at 455 nm, which is comparable to that of commercial gallium phosphide blue PD (0.180 A W^-1 at 470 nm). Moreover, the proposed device exhibits excellent environmental stability under ambient air conditions. These findings will act as a basis for next-generation image sensor technologies, such as vertically stacked red/green/blue PDs.

Key words: Perovskites, Photodetectors, Blue, Composition engineering, Self-powered, Wide bandgap