Electronic origins of dual emission in Mn-doped ZnSe quantum dots

Mn-doped ZnSe quantum dots were synthesized by a hot-injection method and exhibit phase-pure cubic structures with substitutional Mn incorporation. Density functional theory calculations reveal shallow Mn-induced impurity states and p–d hybridization near the valence band, enabling multiple excitation pathways. Optical measurements show band-edge absorption, Mn-related transitions, and dual photoluminescence from ZnSe and Mn2+ centers. A combined mechanism involving excitonic energy transfer, defect-assisted relaxation, and host-to-Mn charge transfer explains the observed optical behavior. These results establish a direct link between Mn-induced electronic modifications and the photophysics of ZnSe quantum dots.