DESIGN AND FABRICATION OF LONG PERSISTENT YELLOW AFTERGLOW IN A COMPOSITE PHOSPHOR VIA ENERGY TRANSFER MECHANISM

A high quality composite phosphor powder of yellowish-green to yellow emission and long afterglow was developed by the process of radiative energy transfer from extremely long afterglow component to the fluorescent component of the composite phosphor followed by the color mixing process. The composite phosphor particles include at least two types of phosphor particles and/or transparent epoxy/silicon resins as binder. The composite phosphor is designed in such a way that the excitation spectrum of the fluorescent component was overlapped as much with the afterglow emission of the persistent component. The composite phosphor emission spectrum can be well tuned from yellowish-green to pure yellow depending on the proportions of the composite phosphors and energy transfer extent. Phosphor includes powders, ceramics and resin composites and can have applications in night vision displays during the energy shortage emergency escape routes and decorative.