Sintering‐Free Phosphor Films for Laser‐Driven Lighting

Abstract Phosphor color converters in the form of ceramics and films are key components in laser‐driven solid‐state lighting, but the high temperature (> 500 °C) required to densify them usually leads to a high loss in quantum efficiency and thermal stability. In this work, a sintering‐free method is reported to fabricate efficient and thermally robust phosphor films on an aluminum substrate by using an Al 2 O 3 inorganic glue at room temperature. The sintering‐free method enables to maintain the initial photoluminescence properties of phosphor particles in the film and thus obtains loss‐free phosphor films. The Y 3 Al 5 O 12 :Ce‐Al 2 O 3 composite phosphor film has a luminance saturation threshold of 16.5 W mm −2 , and allows to generate laser‐driven white light with a luminous flux of 1680 lm, luminous efficiency of 205 lm W −1 , and Correlated Color Temperature (CCT) of 6778 K. Dual‐phosphor films consisting of yellow, red or green phosphors are also fabricated to achieve tunable color temperatures and high color rendering properties of white light. The sintering‐free approach provides an interesting solution to prepare damage‐free and thermally robust phosphor films for laser‐driven solid‐state lighting.