Development of β-SiAlON:Eu2+ phosphor in glass for high-power LED- and LD-based lighting systems using original BaO-B2O3-ZnO-SiO2 (BBZS) composition glass

Abstract

Green-emitting phosphor-in-glass (PiG) materials with a high luminescence efficiency and high color rendering index were developed by co-firing commercial β-SiAlON:Eu2+ phosphor powder and BaO-B2O3-ZnO-SiO2 (BBZS) glass frits possessing a low glass transition temperature (Tg = 560 °C). In agreement with the photoluminescence spectral profiles of powder materials, β-SiAlON:Eu2+ PiG materials showed a broad excitation band from 220 to 500 nm and a narrow emission band at 530 nm under excitation at 450 nm. The β-SiAlON:Eu2+-based PiG exhibited excellent heat resistance, with its relative emission intensity at 200 °C being 83% that at 30 °C. On varying the β-SiAlON:Eu2+ phosphor content in the PiG-based light emitting diodes (LEDs), the highest luminous efficacy was obtained for the 10 wt% β-SiAlON:Eu2+ phosphor-doped PiG sample, and the internal quantum efficiency of this sample under excitation at 450 nm was 56%. By combining the PiG materials prepared in this study with a blue chip-on-board (incident power = 100 mA), the 10 wt% β-SiAlON:Eu2+-based PiG chip module showed a luminous efficacy of 80 lm/Wrad. The PiG-based LED maintained its high luminous efficacy when incident power on the blue chip-on-board increased up to 4 W (220 lm/Wrad). Under blue laser excitation (incident power = 1500 mA), the β-SiAlON:Eu2+-based PiG materials showed a linear relationship between luminous flux and incident laser power. With increasing incident laser power, the luminous flux effectively increased, and the 10 wt% β-SiAlON:Eu2+-based PiG sample showed a luminous efficacy of 300 lm at an incident laser power of 1500 mA.