Modulation of the optical properties of ZnS QD-embedded glass through aluminum and manganese doping

Abstract

Nontoxic cadmium-free ZnS and ZnSe QDs with high quantum efficiency have attracted considerable attention for information displays. However, the applications of ZnS and ZnSe QDs are limited due to their short emission wavelength and low photoluminescence quantum yield (PL QY). Herein, Mn²⁺ singly doped, Al³⁺ singly doped and Mn/Al co-doped ZnS QD-embedded glass were precipitated. Element mapping, XRD, XPS and EPR analysis confirmed the incorporation of Al³⁺ and Mn²⁺ ions in ZnS QDs. It was found that the incorporation of Al³⁺ ions in Mn²⁺:ZnS QDs introduced V_Zn, V_S and Al-related states, which not only modulated the distribution of Mn²⁺ ions, but also introduced a new route for the recombination of charger carriers from ZnS QDs to Mn²⁺ ions. Consequently, dual-band photoluminescence was realized in the Al/Mn:ZnS QD-embedded glass with an improvement in PL QY from 2.2% to 16.8%. Consequently, a series of white light-emitting diodes (WLED) with tunable color temperature and high color-rendering index as high as 95 was fabricated using a single component of co-doped ZnS QD-embedded glass. Results indicate that the co-doping of trivalent and divalent ions in ZnX QDs is effective to improve the PL QY of ZnX QD-embedded glass, and these co-doped ZnX QDs in glass are promising for single-component WLED with a high color rendering index.