Excitation power density dependence of a primary luminescent thermometer based on Er3+, Yb3+: GdVO4 microcrystals operating in the visible

Abstract

A discussion about the calibration of the Er3+,Yb3+:GdVO4 microcrystals as a luminescent primary thermometer based on the known equation of state of Boltzmann distribution of the electronic population of the two Erbium emitting coupled levels has been given. Its validity has been demonstrated. Besides, when Er3+,Yb3+:GdVO4 microcrystals acting as secondary thermometer, it has been proven the dependence of the thermometric ratio based on the integrated intensities of the green visible emissions arising from the two thermally coupled levels of erbium, 2H11/2 and 4S3/2, on the excitation power density for the Er3+,Yb3+:GdVO4 microcrystals. The effect of the excitation power density on the relative thermal sensitivity and temperature resolution has been also analyzed.