ABSTRACT Quantum‐dot (QD)‐embedded glasses are pivotal for advanced photonic applications, yet achieving high photoluminescence performance remains a challenge due to complex interfacial defect states. While recent advances have identified the QD/glass interface as a critical determinant of luminescence, the specific mechanistic role of different alkali metal modifiers in shaping this interface—and consequently the optical properties—remains a significant knowledge gap. Here, we employ atomistic simulations to systematically investigate CdS QDs embedded in 55SiO 2 ‒25R 2 O‒5BaO‒5BaF 2 ‒5B 2 O 3 ‒5ZnO (R = Li, Na, K, or their binary mixtures) glasses. We reveal that the choice of alkali metal directly dictates the interfacial reconstruction: Li cations exhibit a strong preference for bonding with F ions rather than S atoms, whereas Na and K ions display the opposite tendency, driving a higher proportion of S‒alkali interfacial bonds. Furthermore, larger alkali cations induce greater glass network depolymerization, and mixed‐alkali systems manifest pronounced non‐linear deviations in electronic properties. Ultimately, our findings establish a direct composition‒structure‒property relationship, providing experimentalists with a theoretical blueprint to rationally select and mix alkali modifiers to engineer the QD/glass interface and optimize the fluorescence performance of QD‐embedded glasses.
Qian et al. (Wed,) studied this question.