Improving Optical Temperature Sensing Performance of Er3+ Doped Y2O3 Microtubes via Co-doping and Controlling Excitation Power

This work presents a new method to effectively improve the optical temperature behavior of Er3+ doped Y2O3 microtubes by co-doping of Tm3+ or Ho3+ ion and controlling excitation power. The influence of Tm3+ or Ho3+ ion on optical temperature behavior of Y2O3: Er3+ microtubes is investigated by analyzing the temperature and excitation power dependent emission spectra, thermal quenching ratios, fluorescence intensity ratios, and sensitivity. It is found that the thermal quenching of Y2O3: Er3+ microtubes is inhibited by co-doping with Tm3+ or Ho3+ ion, moreover the maximum sensitivity value based on the thermal coupled S-4(3/2)/H-2(11/2) levels is enhanced greatly and shifts to the high temperature range, while the maximum sensitivity based on F-4(9/2)(1)/F-4(9/2(2)) levels shifts to the low temperature range and greatly increases. The sensitivity values are dependent on the excitation power, and reach two maximum values of 0.0529/K at 24 K and 0.0057/K at 457 K for the Y2O3: 1% Er3+, 0.5% Ho3+ at 121 mW/mm(2) excitation power, which makes optical temperature measurement in wide temperature range possible. The mechanism of changing the sensitivity upon different excitation densities is discussed.