Rapid Sintering of High-efficiency Phosphor-in-Glass Films for Laser-driven Light Source

The advanced high-power-density laser-driven light source calls for all-inorganic phosphor-in-glass film (PiGF) composite as color converter to deal with the issues of durability and color tunability. One challenge remains for the PiGF is the thermal erosion and degradation of phosphor, as harsh condition or long duration time is required to densify the film for conventional sintering. With this regard, herein we develop a rapid thermal annealing (RTA) technique to prepare PiGF, attaining a high densification extent (porosity < 3%) by infrared annealing within seconds. A trivial interfacial reaction is detected, leading to almost intact phosphor particles and thus restrained luminous loss. Exemplified by the red-emitting Sr_0.8Ca_0.2AlSiN₃:Eu²⁺ (SCASN:Eu), a record 91.2% internal quantum efficiency (IQE) in the RTA-processed PiGF and a remarkable luminous flux (LF) of 2379 lm and luminous efficacy (LE) of 140 lm/W can be achieved in the PiGF-based phosphor wheel. RTA reduces energy consumption and enables high-throughput sample screening. This preparation strategy also features material universality and design flexibility, hopefully exploring new opto-functional materials and applications.