Realizing efficient broadband near-infrared emission under blue light excitation in Sb-doped zero-dimensional organic tin()-based metal halides coordination structure modulation

Realizing Sb 3+ -activated efficient broadband near-infrared (NIR) emission under blue light excitation remains a significant challenge in lead-free metal halides. To overcome the above difficulties, a coordination structure modulation strategy was adopted, and the broadband NIR emission under blue light excitation was achieved in Sb 3+ -doped zero-dimensional (0D) organic tin( iv ) bromide. Compared to the weak visible light emission with a photoluminescence quantum yield (PLQY) of 2.4% for pure (TBP) 2 SbBr 5 (TBP = tetrabutylphosphonium), Sb 3+ -doped (TBP) 2 SnBr 6 exhibits an efficient broadband NIR emission band at 705 nm with a PLQY of 33.2% upon 452 nm excitation, which stems from self-trapped exciton emission. Combined with experiments and theoretical calculations, we find that the large excited-state lattice distortion degree compared to the ground state and the narrow bandgap are dominant reasons for Sb 3+ -doped (TBP) 2 SnBr 6 showing efficient NIR emission under blue light excitation. Specifically, Sb 3+ -doped (TBP) 2 SnBr 6 also has excellent anti-water stability, existing stably in water for more than 4 hours while maintaining a high luminous efficiency. Based on the excellent stability and unique optical properties of Sb 3+ -doped (TBP) 2 SnBr 6 , a high-performance NIR light-emitting diode (LED) was fabricated by combining Sb 3+ -doped (TBP) 2 SnBr 6 with a commercial blue LED chip, and its application in night vision was demonstrated. Here, we report a new NIR emitter of Sb 3+ -doped tin( iv )-based metal halides via coordination structure modulation, which can exhibit bright broadband NIR emission under blue light excitation with a PLQY of 33.2%.