Sensitive x-ray and extended near-infrared detection with doped perovskite single crystal

Conventional all-inorganic perovskite photodetectors typically exhibit photoresponse limited to the visible region (<800 nm). In this work, we demonstrate a broadband photodetection strategy by introducing Fe dopants into Cs2AgBiBr6 double perovskites, extending the spectral response to ∼1200 nm in the near-infrared (NIR) region. These states enable sub-bandgap photon absorption through transitions involving these defect-induced energy levels, thereby facilitating NIR detection. Furthermore, the Fe-doped Cs2AgBiBr6 (Fe:Cs2AgBiBr6) devices do not compromise the intrinsic X-ray detection performance of Cs2AgBiBr6 while enabling a pronounced enhancement in NIR photoresponse. This study provides an effective doping-driven approach to broaden the operational spectral range of all-inorganic perovskite photodetectors and highlights the potential of defect-state engineering for multifunctional optoelectronic applications.