Multicolor upconversion emission and highly optical temperature sensing based on lanthanide-doped double perovskite Sr2LaNbO6 phosphors

Here we adopt trivalent lanthanide (Ln3+ = Er3+, Er3+/Ho3+, and Yb3+/Tm3+) doped Sr2LaNbO6 (SLNO) as novel upconversion luminescence (UCL) materials for achieving UCL and optical temperature sensing under 980 nm excitation. Specifically, Er3+ single doped Sr2LaNbO6 phosphors present bright high-purity green emission under the 980 nm excitation. While co-doping with the Ho3+ ions, the component of red emission from Er3+ ions increases significantly and sample show a remarkable enhancement of luminescent intensity relative to SLNO:Er3+ sample. The above-mentioned phosphors and Yb3+/Tm3+ co-doped phosphor (blue emission) successfully achieve high-purity trichromatic UCL and mixed white light output in the same host. Furthermore, the temperature sensing performance of the SLNO:Er3+/Ho3+ phosphor based on the fluorescence intensity ratio (FIR) is systematically studied for the first time. The temperature sensing based on the non-thermal coupling levels (NTCLs) exhibit higher sensitivity than that based on the thermal coupling levels (TCLs). The maximum absolute and relative sensitivity for 4F9/2/4I9/2 NTCLs reach 0.16803 K−1 at 427 K and 0.01591 K−1 at 641 K, respectively. Interestingly, NIR emission of 4I9/2 → 4I15/2 transition presents a thermal enhancement, while visible emissions show thermal quenching. These results indicate that the Ln3+ doped Sr2LaNbO6 UCL phosphors have potential applications in the fields of non-contact temperature sensors, full-color displays, and anti-counterfeiting.