Excellent Sensitive Temperature Sensing Performance Based on Fluorescence Intensity Ratio Technique of Yb3+/Er3+ Codoped Gd2(WO4)3

The efficient upconversion (UC) particles based on fluorescence intensity ratio (FIR) technique are developed for application in novel temperature sensors. Herein, Yb 3+ /Er 3+ ‐codoped Gd 2 (WO 4 ) 3 particles are prepared by coprecipitation method and subsequent calcination. The phase structure and surface morphology of the particles are systematically analyzed. The UC emission spectrum of Gd 2 (WO 4 ) 3 :Yb 3+ /Er 3+ particles are mainly composed of two strong emission bands centered at 530 and 551 nm, respectively. Moreover, the optimum doping concentration of Yb 3+ and Er 3+ is fixed at 10% and 2%, respectively. UC emission mechanism based on two‐photon process is investigated by studying the pump power excitation dependence and fluorescence decay behavior of Gd 2 (WO 4 ) 3 :10%Yb 3+ /2%Er 3+ particles. The excellent temperature sensing capability of Gd 2 (WO 4 ) 3 :10%Yb 3+ /2%Er 3+ particles is implemented from thermally coupled levels (TCLs) of Er 3+ . Notably, the maximum absolute sensitivity ( S a ) and relative sensitivity ( S r ) based on TCLs by 2 H 11/2 / 4 S 3/2 levels are 1.39 %K −1 (at 518 K) and 1.18 %K −1 (at 293 K), respectively. As a result, Gd 2 (WO 4 ) 3 :10%Yb 3+ /2%Er 3+ particles have a great potential for application in noncontact temperature sensors.