Robust moisture and thermally stable phosphor glass plate for highly unstable sulfide phosphors in high-power white light-emitting diodes

Abstract

Potential white light-emitting diode (LED) phosphor SrGa2S4, which remains superfluous due to its unstable nature in the presence of moisture, was successfully integrated in a high-power white LED system by developing a glass-based phosphor plate. A glass system with softening temperature at around 600°C, which lies far below the possible decomposition temperature of the sulfide phosphor, provides a stable shield. Physical properties such as thermal stability, transparency, and lower porosity along with chemical stability under operating conditions of the LEDs ensure long-term operability. H2S emission due to the decomposition of sulfide phosphors, which leads to corrosion of LED electrodes, was contained using the developed plate. Higher thermal resistivity of the developed glass system in comparison with conventional resins ensures lower thermal quenching of the luminescence and better color purity.