Long wavelength emissive ZnO/CQDs phosphor with high color purity and its application in sensitive detection of cadmium (II)

Production of color-tunable emission via simple method for upcoming displays and lighting technologies, and their exceptional luminescence provide considerable potential in sensing application. As environmental pollution and diseases brought by cadmium have always been global issues, therefore, it is imperative to develop an inexpensive, quick, easy, and selective approach for detecting trace cadmium. Herein, we describe the preperation of ZnO/carbon quantum dots (ZnO/CQDs) nanocomposite that emits strongly in the yellow-orange zone with the chromaticity coordinates (0.51, 0.47) and a high color purity (CP) value of 94.3%. The as-produced ZnO/CQDs are used as a fluorescence sensor for Cd2+ via quenching mechanism due to competitive coordination between ZnO/CQDs and Cd2+ with the limit of detection (LOD) of 0.14 μM. Additionally, the suggested method can successfully detect Cd2+ in water samples, demonstrating the feasibility and potential uses of the sensing platform. This study may pave the way for the development of environmentally safe, high-performing, and inexpensive color-tunable phosphor for white LEDs and sensing applications.