High quantum yield of In‐based halide perovskites for white light emission and flexible x‐ray scintillators

In-based halides always present low photoluminescence quantum yield (PLQY) because of poor absorption, limiting their potential applications in luminescence-related fields. In this work, zero-dimensional MA(4)InCl(7) [MA(+): CH3NH3+] halides with different Sb3+ doping level are prepared through solvent evaporating method. The Sb3+-doped MA(4)InCl(7) shows a broadband yellow emission with full width at half-maximum of 180 nm and a high PLQY of 84%. Such broadband emission originates from the self-trapped excitons demonstrated by experimental results and theoretical calculations. Additionally, the Sb3+-doped MA(4)InCl(7) is further employed to fabricate white-light-emitting diodes, which possesses high color rendering index of 91 and excellent operating stability up to 400 h. Moreover, flexible Sb3+-doped MA(4)InCl(7) films are also prepared as x-ray scintillators, exhibiting low detection limit of 63.3 nGy(air)/s and high spatial resolution of 10.0 lp/mm. Thus, this work provides guidance to design perovskite-based devices with bright luminescence and x-ray detection with excellent flexibility.