Lead-free hybrid indium perovskites with near-unity PLQY and white light emission using an Sb3+ doping strategy†

Low-dimensional hybrid organic–inorganic metal halides (OIMHs) have been extensively investigated for their structural tunability and unique optoelectronic properties. However, the synthesis of highly photoluminescent lead-free OIMHs remains challenging. To address this issue, we synthesized a series of hybrid OIMHs (DETA)₃InCl₆:xSb³⁺ (DETA = diethylenetriamine, x = 0–15%). With Sb³⁺ doping, the photoluminescence quantum yield (PLQY) is greatly improved from 4.84% to nearly 100%. Moreover, (DETA)₃InCl₆:10%Sb³⁺ single crystals exhibit strong yellow broadband emission originating from self-trapped exciton (STE) radiative recombination. Interestingly, when Sb³⁺ doping is 0.005%, the single crystal doped Sb emits white light at an excitation wavelength of 365 nm with CIE coordinates of (0.35, 0.36). We also explored the effect of Sb³⁺ dopants and STE state formation by DFT calculations and ultrafast transient absorption techniques. This research provides new insights into the design of high-performance photoluminescent materials based on hybrid metal halides.