Photoluminescence from Cu / Mn: ZnSe quantum dots and their phase transformation in silicate glass

To realize the polychromatic and tunable luminescence of ZnSe quantum dots (QDs) in glass, Cu and Mn co-doped ZnSe QDs (Cu/Mn: ZnSe QDs) glass were prepared by melt quenching and subsequent heat treatment method. For the ZnSe QDs glass without Cu and Mn dopants, there is only intrinsic luminescence from ZnSe QDs observed. For Cu/Mn: ZnSe QDs glass, the band edge emission from ZnSe QDs is quenched and the broadband emission from Cu2+/Mn2+ ions is observed, which is resulted by the effective energy transfer from ZnSe QDs to Cu2+/Mn2+ ions. With the increase of heating temperature, the emission spectra of Cu/Mn: ZnSe QDs glass change from green to orange light, which is characteristic luminescence wavelengths of Cu2+ and Mn2+ ions, respectively. For the ZnSe QDs glass without Cu2+ and Mn2+ dopants, ZnSe QDs undergo a phase transformation from the cubic to the hexagonal structure at higher heating temperature (≥610 °C) than those of Cu/Mn: ZnSe QDs glass at 600 °C and Cu-doped ZnSe QDs glass at 580 °C, in addition, For Cu/Mn: ZnSe QDs glass, the phase transformation temperature drops to 600 °C. For Cu-doped ZnSe QDs glass, the phase transformation temperature is further reduced to 580 °C. However, for Mn-doped ZnSe QDs glass, there is no phase transformation. It indicated that Cu2+ promotes the phase transformation of ZnSe QDs.