Achieving efficient self-trapped excitons emission by suppressing defect level in Sb3+ doped metal halide

The field of metal halide engineering has made considerable progress, yet additional studies are needed to completely grasp the intriguing principles that govern their luminescence. In this work, we report a novel zero-dimensional (0D) organic-inorganic metal halide hybrid (OIMH) (C 3 H 12 N 2 ) 2 InCl 7 (C 3 H 12 N 2  = 1,3-propane diamine cation) and reveal its interesting luminescent properties through experimental research and theoretical calculations. The photoluminescence (PL) of (C 3 H 12 N 2 ) 2 InCl 7 is a synergistic combination of intrinsic self-trapped exciton (STE) emission and defect-bound exciton (DBE) emission. Doping with Sb 3+ induces several changes in (C 3 H 12 N 2 ) 2 InCl 7 , including defect passivation, a reduction in the band gap, and structural shrinkage. These modifications result in a transition of PL centers to external STE emission, with the photoluminescence quantum yield (PLQY) increasing from 4.44 % to 68.70 %. Our work proposes, for the first time, the synergistic emission of STE and DBE and reveals the effect of metal ion doping, providing new insights into the mechanisms of materials exhibiting multifunctional exciton emission.