Time-evolution of photoluminescence properties of ZnO/MgO core/shell quantum dots

In situ and ex situ time-evolution of photoluminescence data during growth of ZnO/MgO core/shell quantum dots (Qdots) were used to study the stability of the green-white (CIE: 0.32, 0.41) luminescence from ZnO defects. The ZnO/MgO Qdots, synthesized by a sol-gel process, exhibited a quantum yield of 13% compared with less than 5% for ZnO Qdots. The growth of ZnO Qdots was arrested and the defect emission was stabilized by formation of the MgO shell. UV-Vis absorption data verified the quantum confinement of ZnO/MgO Qdots. Photoluminescence emission from defects in the ZnO/MgO Qdots was stable similar to 70 days at room temperature.