Up-Conversion Luminescence and Optical Temperature Sensing Behaviour of Y₂O₃:Ho³⁺, Yb³⁺ Phosphors

Abstract

The up-conversion (UC) and temperature sensing behaviours of Y2O3:Ho3+, Yb3+ phosphors were investigated. A series of Y2O3:Ho3+, Yb3+ phosphors were synthesized using a solution combustion method. The cubic structure of the Y2O3 with an Ia3¯ 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 Ho3+ from the 5S2 → 5I8, 5F5 → 5I8 and 5S2 → 5I7 transitions were observed, which occurred through UC energy transfer (ET) processes. The Yb3+ ion concentration severely affected the UC emission. The sensing behaviour of the phosphor was investigated through the green (5F4, 5S2 → 5I8) to red (5F5 → 5I8) fluorescence intensity ratio (FIR). The maximum absolute and relative sensitivity values of SA = 0.08 K−1 and SR = 0.64% K−1 were obtained. The results revealed that the prepared Y2O3:Ho3+, Yb3+ phosphor is suitable for optical sensing at high temperatures.

Keywords

• Y₂O₃:Ho³⁺, Yb³⁺ upconversion
• up-conversion energy transfer
• fluorescence intensity ratio
• optical temperature sensing