Rapid Thermal Annealing Technique Enables Ultrafast Sintering of Phosphor-in-Glass Films
Phosphor-in-glass films (PiGFs) are critical color converters for high-power laser-driven lighting and displays, but conventional sintering requires prolonged high-temperature treatment, causing phosphor degradation and high energy consumption. Wang et al. demonstrate a rapid thermal annealing (RTA) technique using high-power (>10 kW) infrared irradiation to sinter PiGFs within ~10 s, achieving heating rates up to 55 °C s−1 and film porosity below 3%. The RTA method reduces energy consumption to 4.3% of conventional sintering, preserves phosphor luminescence, and enables batch production via uniform thermal fields. For Sr0.8Ca0.2AlSiN3:Eu2+ red phosphor-based PiGF, internal quantum efficiency reaches 91.2% (vs. 82.8% for conventional), with thermal stability of 90.4% at 200 °C. Under 455 nm blue laser at 27 W mm−2, it delivers 2379 lm and 140 lm W−1. β-SiAlON:Eu2+ and Sr0.8Ca0.2AlSiN3:Eu2+ PiGFs in laser-driven liquid crystal displays achieve 3502 lm and 206 lm W−1. The RTA technique is general for oxides, nitrides, oxynitrides, sulphides, and halides, offering a scalable route to high-performance PiGFs.