Photolytically and Thermally Stable Ligand-Engineered Mn ²⁺ -Doped ZnS Quantum Dots with High Color Rendering Index for White Light Emission

We report a postsynthetic ligand engineering strategy for Mn2+-doped ZnS quantum dots (QDs) to achieve stable white light emission (WLE) with high color rendering index (CRI), enhanced photostability, and thermal resilience. A terpyridine-functionalized pyrene ligand coordinates with surface Zn2+/Mn2+ cations via nitrogen chelation, effectively passivating the orange-emitting QD surface and providing cyan emission through ligand-centered photoluminescence. The combination of cyan ligand emission and orange Mn2+ emission produces balanced WLE with CIE coordinates of (0.31, 0.34), a correlated color temperature of 6437 K, and a CRI of 91. The ligand-engineered QD (LE-QD) nanocomposites exhibit excellent ambient stability over one month and retain consistent optical performance across 25–55 °C, demonstrating strong thermal resilience. This work highlights coordinated ligand design as a scalable strategy to tailor emission, enhance QD stability, and produce environmentally robust, high-performance materials for solid-state lighting and optoelectronics.