Multifunctional optical thermometry using dual-mode green emission of CaZrO(3):Er/Yb/Mo perovskite phosphors

The weak emission intensity of rare-earth element-doped dual-mode materials leads to low-sensor sensitivity, which is a challenge in optical sensor applications. The present work achieved high-sensor sensitivity and high green color purity based on the intense green dual-mode emission of Er/Yb/Mo-doped CaZrO(3) perovskite phosphors. Their structure, morphology, luminescent properties, and optical temperature sensing properties have been investigated in detail. Phosphor shows a uniform cubic morphology with an average size of approximately 1 μm. Rietveld refinement confirms the formation of single-phase orthorhombic CaZrO(3). Under the excitation of 975 and 379 nm, the phosphor emits pure green up and down-conversion (UC and DC) emission at 525/546 nm corresponding to (2)H(11/2)/(4)S(3/2)–(4)I(15/2) transitions of Er(3+) ions, respectively. Intense green UC emissions were achieved because of energy transfer (ET) from the high-energy excited state of Yb(3+)–MoO(4)(2−) dimer to the (4)F(7/2) level of Er(3+) ion. Furthermore, the decay kinetics of all obtained phosphors confirmed ET efficiency from Yb(3+)–MoO(4)(2−) dimer to Er(3+) ions, leading to strong green DC emission. Moreover, the DC of the obtained phosphor shows that a sensor sensitivity value of 0.697% K(−1) at 303 K is higher than the UC (0.667% K(−1) at 313 K) because the thermal effect generated by the DC excitation source light is ignored compared with UC luminescence. CaZrO(3):Er–Yb–Mo phosphor shows intense green dual-mode emission with high green color purity, 96.50% of DC and 98% of UC emissions, and high sensitivity, making it suitable for optoelectronic devices and thermal sensor applications.