An optical thermometer with high sensitivity and superior signal discriminability based on dual-emitting Ce3+/Eu2+ co-doped La5Si2BO13 thermochromic phosphor

Abstract

A novel non-contact optical thermometer, qualified with high sensitivity and temperature resolution, is urgently needed for temperature measuring of micro devices, moving objects and specific severe environments. Hence, a series of dual-emitting La5Si2BO13:Ce3+,Eu2+ phosphors were synthesized. The two ions show diverse responses with the changing in temperature. The variational emissions of Ce3+ and Eu2+ can be converted to FIR (fluorescence intensity ratio) signals. The maximal absolute sensitivity Sa and relative sensitivity Sr reach up to 0.07526%/K and 3.2241%/K, respectively. It is worthy noting that the Sa and Sr possess the same variation tendency and both have high values in the low temperature region (293–373 K), showing the great temperature measuring property especially in low temperature region. The temperature sensing characteristics are superior to the results of most previous reports. The energy transfer (ET) process is certified to occur from Ce3+ to Eu2+ ions. These studies indicate that La5Si2BO13: Ce3+,Eu2+ phosphor could have a good prospect for optical thermometry.