Concentration effects on the FIR technique for temperature sensing.

Different concentrations of Er 3+ doped Y 2 O 3 ceramics are synthesized. Under the 966 nm excitation, it is found that the ratios of red to green emissions are obviously enhanced with temperature for high doped sample, which is attributed to the combined temperature-dependent processes. Besides that, variations of fluorescence intensity ratio of green upconversion emissions in Er 3+ :Y 2 O 3 ceramics have been studied as a function of temperature. A maximum sensitivity of less than 0.003 K −1 is obtained in the high doped sample, whereas it is above 0.005 K −1 in the low doped sample. Concentration effects on the temperature sensing behaviors are discussed. In addition, similar phenomenon is found in Er 3+ /Yb 3+ codoped NaYF 4 nanocrystals. [ABSTRACT FROM AUTHOR]