Luminescence nanothermometry using a trivalent lanthanide co-doped perovskite

This study investigates in detail the laser-mediated upconversion emission and temperature-sensing capability of (Ca_0.99- Yb_0.01Er )TiO₃. Samples were prepared at different concentrations to observe the effect of erbium on upconversion while increasing its concentration and keeping all the other parameters constant. Doping is a widespread technological process which involves incorporating an element called a dopant in a lower ratio to the host lattice to derive hybrid materials with desired properties. The (Ca_0.99- Yb_0.01Er )TiO₃ perovskite nanoparticles were synthesized via a sol-gel technique. The frequency upconversion was performed using a 980 nm laser diode excitation source. X-ray diffractometry (XRD) confirmed that the synthesized samples are crystalline in nature and have an orthorhombic structure. The temperature-sensing ability was examined using the fluorescence intensity ratio (FIR) algorithm of two emission bands (²H_11/2 → ⁴I_15/2 and ⁴S_3/2 → ⁴I_15/2) of the Er³⁺ ion. Temperature-dependent upconversion luminescence is observed over a broad temperature range of 298-623 K. The maximum sensor sensitivity obtained is 6.71 × 10^-3 K^-1 at 110°.