Design- and optimizing zinc gallate blue phosphor toward versatile applications in photo- and electroluminescence

The development of the blue light-emitting device is receiving much attention due to its wide application in display and optoelectronics matter. Herein, the cost-effective self-activated ZnGa2O4 blue phosphors have been demonstrated in photoluminescence as well as the alternating-current powder-based electroluminescence device. The phosphors are prepared in a facile method solid-state reaction with optimum annealing temperature and mixed with an organic binder before being coated in the ITO glass substrate through the screen-printing technique. In a low threshold voltage (0.4 x 104 V/cm in an electric field), it emits a broad spectrum from violet to the green region with an emission center at 440 nm originating from the defect vacancies in the ZnGa2O4 lattice. It has excellent stability and afterglow effect under ultraviolet exposure and a superior lifetime maintaining an intensity of more than 80% for 3000 min without any encapsulation under AC-driven voltage. In addition, due to the high radiation energy from the blue color emission, it can be used as a color-down conversion for red-yellowgreen phosphors and photocatalysis in a dilute solution of TiO2 and methylene blue.