High‐Performance Near‐Infrared Photodetector Enabled by Tin‐Based Perovskite Inverse Opal Towards Secure Information Transmission

ABSTRACT Tin‐based perovskites are widely used in near‐infrared (NIR) photodetectors owing to their excellent optoelectronic properties and environmental friendliness. However, their performance is severely limited by high defect densities and pronounced instability. Herein, we report the successful fabrication of high‐performance NIR photodetectors based on an inverse opal (IO) photonic crystal structure of formamidinium tin iodide (FASnI 3 ) perovskite. This structural design significantly reduces the defect density of the Sn‐based perovskite functional layer and markedly enhances its stability. Notably, a bifunctional organic additive, 1,4‐butanediammonium iodide (BDADI), plays a key role in enabling the formation of perovskite IO structures by effectively regulating the colloidal chemistry and crystallization kinetics of FASnI 3 . The resulting ordered BDADI‐modified FASnI 3 (FASnI 3 ‐BDADI) IO architecture not only enhances light harvesting via slow‐photon effects but also facilitates efficient carrier transport. As a result, the IO photodetector achieves record‐breaking responsivity (5.90 A·W −1 ) and a champion detectivity (1.06 × 10 14 Jones) at 808 nm, along with excellent unencapsulated stability attributed to the lotus effect of photonic crystal. Leveraging its superior performance and stability, we demonstrate, for the first time, the application of such high‐performance NIR perovskite photodetectors in interference‐resistant image transmission over a distance of up to 30 m.