Unique composite architecture of phosphor-in-glass film coated on different heat-conducting substrates for high-brightness laser lighting
Xin Liu, Mingxiang Chen, Jiuzhou Zhao, Hongjin Zhang, Peng Yang, Qing Wang
Abstract
Next-generation high-brightness laser lighting confronts a key challenge in developing static luminescent materials with remarkable optical-thermal performances and low cost. Herein, a unique composite architecture of Y<sub>3</sub>Al<sub>5</sub>O<sub>12</sub>:Ce<sup>3+</sup> (YAG) phosphor-in-glass film coated on different heat-conducting substrates (PiGF@HCSs), i.e., PiGF@sapphire, PiGF@Al<sub>2</sub>O<sub>3</sub>, PiGF@AlN, and PiGF@BN-AlN composites, was designed and prepared by a simple film printing and low-temperature sintering technology. The heat-conducting substrates significantly affect the luminescence saturation and phosphor conversion of PiGF@HCSs, making the substrates with higher thermal conductivity (TC) can bear higher laser power density (LPD) and higher reflectivity can enable higher luminous efficacy (LE). As a consequence, the PiGF@sapphire realizes a luminous flux (LF) of 2076 lm@12 W/mm<sup>2</sup>, which is higher than the PiGF@Al<sub>2</sub>O<sub>3</sub> of 1890 lm@15 W/mm<sup>2 </sup>and the PiGF@AlN of 1915 lm@24 W/mm<sup>2</sup>, while the PiGF@BN-AlN enables a maximum LF of 3058 lm@21 W/mm<sup>2</sup>. Furthermore, the LE of PiGF@BN-AlN reaches up to 194 lm/W, which is 1.6 times that of PiGF@AlN, while that of PiGF@sapphire and PiGF@Al<sub>2</sub>O<sub>3</sub> are 192 lm/W and 150 lm/W, respectively. The working temperature of PiGF@AlN is only 93.3℃ under the LPD of 9 W/mm<sup>2</sup>, while that of PiGF@sapphire, PiGF@Al<sub>2</sub>O<sub>3</sub>, and PiGF@BN-AlN rises to 193.8℃, 133.6℃, and 117℃, respectively. These findings will provide the guiding idea for the commercial applications of PiGF@HCS converters in high-brightness laser lighting and display.