Zinc Gallate (ZnGa2O4) has been reported in various studies as a good host phosphorescent material. Therefore, the changes in optical properties resulting from doping various metal elements into ZnGa2O4 were very pronounced. However, since ZnGa2O4 is mostly synthesized through solid-state reactions, high temperature and pressure reaction conditions were required, and its low dispersibility often limited its applications. In this study, we synthesized normal spinel structured ZnGa2O4 nanocrystals through a colloidal method. Lanthanide doping specifically with Europium and Terbium resulted in red (614 nm, photoluminescence quantum yield (PLQY): 2.2%) and green (545 nm, PLQY: 13.6%) emissions under 254 nm UV excitation. By applying the novel co-doping system of Europium and Terbium to the synthesis of colloidal ZnGa2O4 for the first time, we were able to achieve various color conversions including green, red, and white by adjusting amount and ratio of Lanthanide.
