Simultaneous 100% PLQY of Mn2+ Emission and High Pb Substitution via Sr2+ Doping in Mn-CsPbCl3 Nanocrystals

Abstract

Doping Mn²⁺ ions into all-inorganic cesium lead halide perovskite nanocrystals (PNCs) offers a unique pathway for inducing new emission channel and reducing lead toxicity. However, the concentration quenching at high Mn²⁺ levels degrades the photoluminescence quantum yield (PLQY), posing a formidable challenge for reconciling a high Pb substitution rate with a high Mn²⁺ emission PLQY. In this study, we report an efficient approach to simultaneously achieve 100% PLQY of Mn²⁺ emission and 18.58% Pb substitution rate in Mn²⁺/Sr²⁺ co-doped CsPbCl3 NCs. This balance between high PLQY and high Pb substitution rate is realized due to the reducing defect density and mitigating lattice distortion through Sr²⁺ doping, thus enhancing energy transfer efficiency from excitons to Mn²⁺ (70.85% vs 87.88 %), and alleviating the microstrain induced by lattice distortion to facilitate the occupation of Pb²⁺ sites. The stability-enhanced Mn/Sr-CsPbCl₃@PMMA nanocrystal-polymer composite film was further fabricated for the construction of white light-emitting diode (WLED), which achieved desirable white-light coordinates (0.338, 0.346). This work not only enriches the understanding of the luminescence properties in Mn²⁺-doped PNCs, but also provides new insights for developing low-toxicity light-emitting devices.