Realization of phosphor-in-glass thin film on soda-lime silicate glass with low sintering temperature for high color rendering white LEDs

Y3Al5O12:Ce3+ phosphor-in-glass (PiG) thin film on soda-lime silicate glass substrate has been applied using screen-printing method for generation of white LED light in modern day lighting. In this work, a glass composition in a ZnO-Bi2O3-B2O3 system has been optimized to have low softening temperature, as well as matching the refractive index with that of Y3Al5O12:Ce3+ phosphor. The sintering of the PiG layers was performed at a relatively low temperature of 560°C to avoid the chemical degradation of the phosphors. We employed a combination of powder x-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, UV-visible absorption and fluorescence spectroscopy, as well as Fourier transfer infrared spectroscopy to study the detailed structure and different spectral properties of PiG samples. This Y3Al5O12:Ce3+-based PiG exhibits an external quantum efficiency of ∼40%, even with its thickness of only 5 μm. Under the excitation of the blue laser diode source, the synthesized PiG thin film has exhibited a bright white light with high color rendering index (CRI=92 and CCT=3877 K). The synthesized PiG sample was used to design a high-power white-light-emitting diode module by combining it with a 3 W blue LED on-board chip. This module is expected to be a promising candidate for next-generation illumination at a relatively lower cost, with long-term reliability.