Near-ultraviolet trigger Er³⁺ activation green trifunctional material for solid-state lighting, forensic fingerprint...

The Er³⁺ doped Sr₉La₂(WO₆)₄ phosphor was prepared via the solid-state reaction method. Through a series of tests, this study validated its dual functionality in solid-state lighting and non-contact optical temperature sensing. Under excitation at 381 nm, the material prepared emitted intense green light. When integrated into LED devices, the LED produced bright white light with a color rendering index (CRI) near 94, a moderate color temperature, and chromaticity coordinates that fell within the white light region. Based on the fluorescence intensity ratio (FIR) principle, the phosphor exhibited exceptional sensitivity in the temperature range of 298-523 K. As the temperature increased, the maximum absolute sensitivity reached 4.6222 % K^-1 at 583 K, and the maximum relative sensitivity of 2.5385 % K^-1 was observed at 348 K, outperforming most reported temperature sensing materials of similar type. Furthermore, the fluorescent LFP images prepared with Sr₉La₂(WO₆)₄:0.09Er³⁺ phosphor have excellent visualization, with high resolution and contrast, and are able to identify 1-3 level details well. The results show that Sr₉La₂(WO₆)₄: xEr³⁺ phosphors have potential applications not only in w-LEDs and visualization of potential fingerprints, but also in optical sensors for environmental monitoring and temperature sensing.