A novel PiGF@diamond color converter with a record thermal conductivity for laser-driven projection display

High-brightness laser lighting is confronted with crucial challenges in developing laser-excitable color converting materials with effective heat dissipation and super optical performance. Herein, a novel composite of phosphor-in-glass film on transparent diamond (PiGF@diamond) is designed and fabricated via a facile low-temperature co-sintering strategy. The as-prepared La₃Si₆N₁₁: Ce³⁺ (LSN: Ce) PiGF@diamond with well retained optical properties of raw phosphor shows a record thermal conductivity (TC) of ~599 W·m^-1·K^-1, which is about 60 times higher than that of currently well-used PiGF@sapphire (~10 W·m^-1·K^-1). As a consequence, this color converter can bear laser power density (LPD) up to 40.24 W·mm^-2 and a maximum luminance flux (LF) of 5602 lm without luminescence saturation due to efficient inhibition of laser-induced heat accumulation. By further supplementing red spectral component of CaAlSiN₃: Eu²⁺ (CASN: Eu), the PiGF@diamond based white laser diode (wLD) is sucessfully constructed, which can yield warm white light with a high color rendering index (CRI) of 89.3 and find practical LD-driven applications. The findings will pave the way for realizing the commercial application of PiGF composite in laser lighting and display.

https://onlinelibrary.wiley.com/doi/10.1002/adma.202406147