Buried Grating Enables Fast Response Self‐Powered Polarization‐Sensitive Perovskite Photodetectors for High‐Speed Optical Communication and Polarization Imaging

Polarization-sensitive perovskite photodetectors (PSPPDs) have demonstrated great potential for acquiring multidimensional data in remote sensing, security, and optical communication fields. However, requirements of external power supplies and polarization systems, slow response, and poor long-term stability restrict PSPPDs' further development. Herein, a self-powered PSPPD with buried grating structures induced by ultrafast laser direct writing is designed. Remarkably, polarization detection can be achieved without the assistance of conventional optical and mechanical structures. The buried grating structure can reduce light reflection through grating diffraction, facilitating light convergence and enhancing light trapping within the active layer of the PSPPD. As expected, the PSPPD exhibits excellent external quantum efficiency (532 nm, 0 V bias), responsivity (532 nm, 0 V bias), and dark current values of 93.93%, 403 mA W^-1, and 5.95 × 10^-10 A, respectively. Notably, the raising/falling time is less than 2 µs, which is one of the shortest response times among PSPPDs with grating structures to the best of this knowledge. Moreover, after 120 days of air exposure, the manufactured PSPPDs remain highly effective in fast optical communications, manifesting their exciting potential to produce reliable, high-performance devices economically and efficiently for future applications.