Band Alignment Engineering in n s ² Electrons Doped Metal Halide Perovskites

Abstract Luminescent metal halide perovskites (MHPs) open new avenues for highly efficient radiation detection. To challenge the state‐of‐art technology, fundamental understanding of factors controlling radiation light yield of MHP scintillators is urgent. Herein, a design method is established by simultaneously considering charge‐transfer and recombination efficiencies via band alignment engineering in doped MHPs materials, and this strategy is corroborated experimentally and computationally by applying it to the luminescence of n s 2 electron (Sb 3+ , Bi 3+ , and Te 4+ ) doped vacancy‐ordered double perovskite Cs 2 ZrCl 6 . Alloying Te 4+ into Cs 2 ZrCl 6 is optimized and significantly improves the scintillation performance, including a twofold increase in light yield and a threefold increase in detection limit over pristine Cs 2 ZrCl 6 , and high‐resolution X‐ray imaging with 20 μm for 2D and 0.2 mm for 3D imaging. It is believed that doping engineering in MHPs enabling band alignment method holds great potential for the development of next‐generation MHP scintillators.