A tri-color phosphor-in-glass strategy in ultra-low melting glass: achieving full-spectrum white light at low 350 °C

Traditional phosphor-in-glass (PiG) composites require high preparation temperatures, which can cause thermal degradation of phosphors. Therefore, comparative studies on glass systems were conducted to explore the feasibility of preparing high-performance PiG at lower temperatures. Through systematic comparison of various glass systems, an ultra-low melting tin fluorophosphate glass was selected as the matrix, enabling the successful preparation of full-spectrum daylight-like PiG at a significantly reduced temperature of 350 °C. This temperature is far lower than the processing temperatures required for tellurite or borosilicate glass systems. The mild preparation conditions effectively preserved the structural integrity of the incorporated RGB phosphors (green (Ba,Sr) 2 SiO 4 :Eu 2+ , blue BaMgAl 10 O 17 :Eu 2+ , and red CaAlSiN 3 :Eu 2+ ), as confirmed by XRD and SEM analyses, which showed uniform dispersion of phosphors in the glass matrix and minimal interfacial reactions. The white LED packaged with this PiG exhibited a continuous full spectrum covering 420–780 nm and excellent color rendering properties (R a  = 92, R 9  = 92.2, R 13  = 92.7), with a spectral profile close to natural daylight, making it suitable for human-centric lighting. Furthermore, the PiG retained approximately 90% of its thermal stability at 423 K. By combining glass system comparison with low-temperature preparation techniques, this study achieved outstanding optical performance while significantly reducing the fabrication temperature, providing a viable material pathway for the development of full-spectrum daylight-like LEDs and their potential applications in health-conscious lighting.