High-performance triple-cation perovskite photodetectors enabled by transparent interdigitated electrodes and plasmonic substrate engineering

We present a high-performance perovskite photodetector based on a triple-cation composition, (Cs₀.₀₆FA₀.₇₉MA₀.₁₅)Pb(I₀.₈₅Br₀.₁₅)₃, using a planar metal-semiconductor-metal architecture with transparent indium tin oxide interdigitated electrodes (IDEs) and a plasmonic substrate. The transparent IDEs enhance light absorption and improve carrier collection by minimizing optical shadowing and reducing carrier transit distance. Simultaneously, the plasmonic substrate induces dipole-image dipole interactions that suppress radiative recombination, thereby extending carrier lifetimes and increasing responsivity. This dual-enhancement approach yields superior photoresponsivity and response speed compared to control devices and outperforms several state-of-the-art designs reported in recent literature. Unlike traditional methods that rely on chemical passivation or optical cavities, our design leverages intrinsic material properties and straightforward fabrication processes. This work offers a scalable pathway to high-speed, high-sensitivity perovskite photodetectors suitable for integrated optoelectronic and imaging systems.