NUV light-induced visible green emissions of Erbium-doped hierarchical Bi2Zr2O7 structures

We reported a facile strategy to synthesis of Er³⁺ doped Bi₂Zr₂O₇ nanophosphors via hydrothermal route using Aloe Vera gel as a bio - surfactant. The photoluminescence spectra exhibit intense peaks centered at ~524, 547 and 660 nm, which were attributed to ²H_11/2 → ⁴I_15/2, ⁴S_3/2 → ⁴I_15/2 and ⁴F_9/2 → ⁴I_15/2 transitions of Er³⁺ ions, respectively. The highest photoluminescence intensity was achieved in 5 mol % of Er³⁺ ions. The electric dipole-quadrupole (d-q) interaction was responsible for the concentration quenching. The fluorescence intensity ratio technique was utilized for optical thermometric properties of the nanophosphors in the temperature range of 303-463 K. At lower temperature (282 K) the relative sensor sensitivity of the optimized nanophosphor was found to be ~0.0621 K^-1. Thermoluminescence glow curves of 5 mol % Er³⁺ ions doped nanophosphor irradiated with γ-rays showed two peaks at ~120 and 203 °C. A thermoluminescence glow peak at ~120 °C showed good linearity with dose, simple glow curve structure, minimal fading and good reproducibility. The above results clearly showed that the optimized nanophosphor is quite useful in WLED's, TL dosimetry and optical thermometry applications.