Multistimuli-Responsive Polychromatic Luminescence in Cs ₂ NaLuCl ₆ Double Perovskites for Bifunctional Optical Sensing

High Resolution Image Download MS PowerPoint Slide To design multistimuli-responsive polychromatic luminescence, the Sb 3+ -doped and Sb 3+ /Sm 3+ -codoped Cs 2 NaLuCl 6 double perovskites were synthesized. These materials show tunable emission under 345 nm excitation, due to the Sb 3+ → Sm 3+ energy transfer. The perovskites stimulated by high temperature exhibited blue to white polychromatic luminescence, owing to the different responses of self-trapped exciton (STE) and Sb 3+ emissions. By analyzing spectroscopic parameters derived from temperature-dependent emission spectra, the thermometric properties of the synthesized perovskites were investigated. Herein, the maximum relative temperature sensitivities of the studied samples were 1.13%, 2.49%, and 0.43% K –1, by using the fluorescence intensity ratio value of the STE to Sm 3+ emissions, decay time, and color coordinate as temperature indicators, respectively. Furthermore, the pressure-triggered structural and spectral evolution of the compounds was characterized. Pressure-dependent Raman spectra confirmed that the multistage phase transition occurred under high pressure. The STE and Sm 3+ emissions changed with pressure, i.e ., from blue to pink and finally to white light, making them suitable for visual pressure monitoring. The Sm 3+ pressure-dependent spectral shift resulted in a sensitivity of 0.57 nm GPa –1 . Based on the Sm 3+ lifetime, the maximum pressure sensitivity was estimated as 24.22% GPa –1, indicating that Sb 3+ /Sm 3+ -codoped Cs 2 NaLuCl 6 double perovskites can be applied in high-sensitivity optical thermometry and manometry.