Controllable Synthesis of Ba2SiO4:Eu2+ Phosphors with Uniform Size and Shape for Micro-LED Color Conversion

With the rapid advancement of display technology, microlight-emitting diodes (Micro-LED) have emerged as promising candidates for the next generation of display devices due to their miniaturized structure. Unfortunately, phosphors synthesized via a conventional solid-state method often exhibit irregular morphology and large particle sizes that are comparable to or even larger than those of the Micro-LED chip, which severely impedes their application. In this study, we have employed a diffusion-controlled solid-state reaction to synthesize a series of Ba1.9SiO4:0.1Eu2+ phosphors with micrometer size and uniform shape. Under high-temperature calcination BaCO3 and uniform SiO2 particles, Ba2SiO4:Eu2+ particles were formed and inherited the morphology of SiO2 particles via the diffusion of barium ion from the surface to the interior of the SiO2 particles and the reaction between them. These as-obtained phosphors exhibit excellent luminous performance. Under 365 nm excitation, photoluminescence spectra exhibited a narrow emission band with a peak at 504 nm and a full width at half-maximum (fwhm) of 57 nm. The external quantum efficiency is up to 66.84%. Employing this material as a green emitter, the as-prepared LED device has a color gamut of 115% National Television System Committee (NTSC) space. This work opens pathways to the synthesis of phosphors with controlled shape and size by manipulating the diffusion process, which could promote the application of phosphor materials in Micro-LED.