| Summary: | The up-conversion (UC) and temperature sensing behaviours of Y<sub>2</sub>O<sub>3</sub>:Ho<sup>3+</sup>, Yb<sup>3+</sup> phosphors were investigated. A series of Y<sub>2</sub>O<sub>3</sub>:Ho<sup>3+</sup>, Yb<sup>3+</sup> phosphors were synthesized using a solution combustion method. The cubic structure of the Y<sub>2</sub>O<sub>3</sub> with an Ia<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mover accent="true"><mrow><mn>3</mn></mrow><mo>¯</mo></mover></mrow></semantics></math></inline-formula> space group was analysed by using X-ray powder diffraction. Scanning electron microscopy was conducted to study the surface morphologies of the UC phosphors. Under 980 nm excitation, the UC emissions of Ho<sup>3+</sup> from the <sup>5</sup>S<sub>2</sub> → <sup>5</sup>I<sub>8</sub>, <sup>5</sup>F<sub>5</sub> → <sup>5</sup>I<sub>8</sub> and <sup>5</sup>S<sub>2</sub> → <sup>5</sup>I<sub>7</sub> transitions were observed, which occurred through UC energy transfer (ET) processes. The Yb<sup>3+</sup> ion concentration severely affected the UC emission. The sensing behaviour of the phosphor was investigated through the green (<sup>5</sup>F<sub>4</sub>, <sup>5</sup>S<sub>2</sub> → <sup>5</sup>I<sub>8</sub>) to red (<sup>5</sup>F<sub>5</sub> → <sup>5</sup>I<sub>8</sub>) fluorescence intensity ratio (FIR). The maximum absolute and relative sensitivity values of S<sub>A</sub> = 0.08 K<sup>−1</sup> and S<sub>R</sub> = 0.64% K<sup>−1</sup> were obtained. The results revealed that the prepared Y<sub>2</sub>O<sub>3</sub>:Ho<sup>3+</sup>, Yb<sup>3+</sup> phosphor is suitable for optical sensing at high temperatures.
|
|---|