Weexemplify the Fr(Nho3 phosphor to demonstrate that the performance of the temperature sensor based thermal effect of fluorescence intensity ratio(FIR) af 98L-nm-upconverted Ero green 530 and 550 nm emissions can be improved by using KBr-diluted phosphor. The sensing performance of the diluted phosphor plate was studied as a function or KBr Er(NbO 3 unular ratio fr 0:1 uu 100:1. The results shuw that the KB dilution enables to enhance the finorescence intensity and increase the temperature sensitivity. Meanwhile, the KBr itself does not affect either the Era spectroscopic properties or the FIR value. There is an optimum KBr: Er(Nbo33 molar ratio within 15:1 and 20:1, for which the 530(550) nm signal increascs by 30% (20%) and the relative sensitivity al the physiological LEmperature increases by 14%.