Gradient heterostructure perovskite single crystals enable the improvement of radiative recombination for scintillator application

Recently, organic-inorganic hybrid perovskites (OIHPs) are rising as promising candidates for light-emitting applications, due to their superior optical properties. High performance light-emitting applications such as scintillators require minimum non-radiative recombination and high fractions of radiative recombination. Here, we report a simple solution-processing strategy for the synthesis of funnel-type CH₃NH₃(MA)PbCl₃/CH₃NH₃(MA)PbBr_xCl_3-x heterostructure perovskite materials that improve the light emission performances. The single crystal X-ray diffraction pattern indicates that the lattice mismatch is only ∼3.24% in the heterointerface. The halide gradient is helpful for driving the photoexcited carriers from the internal high bandgap material to the low bandgap light-emitter layer. The steady-state photoluminescence (PL) and radioluminescence (RL) spectra show that the luminescence intensity has been significantly improved by this heterostructure perovskite. Time-resolved photoluminescence (TRPL) exhibits carrier transport along the halide gradient. Our research suggests that the gradient halide perovskite heterostructure with specific optical properties could be a prospect for commercial scintillator applications.