High‐Performance and Stable Dual‐Nanograting‐Perovskite‐Based Near‐Infrared Photodetector

Abstract Potential applications of perovskite materials in near‐infrared (NIR) photodetectors are hindered by their instability and low absorption. In this study, dual nanogratings and upconversion nanoparticles (NaYF 4 :20%Yb, 2%Er) are introduced to enhance the stability of MAPbBr 3 and extend its spectral response to the NIR range. A photodetector with responsivity of 2.9 A·W −1 and detectivity of 1.34×10 11 Jones at 980 nm is developed using this approach. The device maintained 78.6% performance after 4 months of air exposure and 72.4% performance after 3000 bending cycles, demonstrating significant improvements in stability and flexibility.