Unlocking Near 100% PLQY: The Impact of Post-Treatment on Emission Efficiency of Mn2+: CsPbCl3 Nanocrystals

Mn(2+ )doped CsPbCl3 nanocrystals (Mn2+: CsPbCl3 NCs) show immense promise in lighting and display technologies owing to their outstanding optical characteristics. Nonetheless, high defect density, inefficient Mn2+ doping, and poor structural robustness pose considerable challenges in the synthesis of Mn2+: CsPbCl3NCs with high photoluminescence quantum yield (PLQY) and long-term stability. This study introduces an eco-friendly room-temperature post-treatment method utilizing MgCl2/oleylamine solution, boosting the total PLQY of the NCs from 65% to 98%, including a 30% increase for Mn2+ emission. Additionally, the post-treatment significantly improves the NCs' resilience against UV light, retaining 80% of their initial PL intensity after 120 hours of UV exposure. Comprehensive analyses including density functional theory simulation and temperature-dependent PL spectra suggested that the PLQY enhancement is due to the improved Mn(2+ )doping efficiency and the effective passivation of native vacancy defects. The stability of the NCs is enhanced by replacing Pb2+ with Mg(2+ )and Mn2+, mitigating lattice distortions within the [PbCl6](4- )octahedral framework. The color rendering index of white light-emitting diodes fabricated with the post-treated Mn2+: CsPbCl3 NCs achieves an exceptional value of 98. This work offers novel insights into the fabrication of high-PLQY Mn2+: CsPbCl3 NCs, advancing the practical deployment of perovskite nanomaterials in various industries.