Flexible droplet printing of prominently luminescent patterns of europium-doped yttrium oxide nanospheres

Flexible techniques for producing luminescent patterns with high-resolution and moderate efficiency at the microscale are potentially important for pattern display, customized anti-counterfeiting and data security. An innovative droplet-based aerosol jet printing procedure has been developed for the creation of prominently luminescent patterns of europium-doped yttrium oxide (Y2O3:Eu3+) inorganic phosphors in case of a rather low calcining temperature. Microscale luminescent patterns of pomegranate-shaped Y2O3:Eu3+ nanospheres were effectively created by synchronizing the droplet deposition behavior and the microreactions therein. The deposition temperature was crucial to the pattern development accompanying a morphological transformation from dense film to spherical nanostructures by providing an anisotropic evaporation regime. The red emission of the printed luminescent patterns was nearly identical to that of the equivalents calcined at 1000 °C, indicating the possibility for future applications in flat panel display systems.