Temperature dependence of up-conversion luminescence and sensing properties of LaNbO4: Nd3+/Yb3+/Ho3+ phosphor under 808 nm excitation

LaNbO4: Nd3+/Yb3+/Ho3+ phosphor was prepared by a conventional high temperature solid-state reaction method. The temperature dependence of up-conversion (UC) luminescence property of LaNbO4: Nd3+/Yb3+/Ho3+ phosphor under 808 nm excitation and the potential application of exploiting the red-to-green UC emission intensity ratio (IR/IG) of Ho3+ in temperature sensing were studied. Two-photon processes were confirmed to be responsible for both the green and the red UC emissions at different temperatures by analyzing the excitation power density dependent UC luminescence spectra measured at different temperatures. The energy level diagram was drawn to analyze the UC luminescence mechanism of Ho3+. In addition, it was found that the ratio IR/IG of Ho3+ was independent of the excitation power density of 808 nm laser under the current experimental condition, but it was sensitive to the temperature. And the temperature dependent UC luminescence spectra displayed that the ratio IR/IG exhibited a good linear increasing tendency with temperature rising. The obtained temperature sensing sensitivity was 2.04 x 10(-3) K-1 in the temperature range of 303-693 K. The results suggest that LaNbO4: Nd3+/Yb3+/Ho3+ phosphormay be a good candidate for application in optical temperature sensors. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

The LaNbO4: Nd3+/Yb3+/Ho3+ phosphor was prepared using a conventional high temperature solid-state reaction method. The study focused on the temperature-dependent luminescence properties of the phosphor and its potential application in temperature sensing. It was found that the red-to-green UC emission intensity ratio (IR/IG) of Ho3+ showed a linear increasing tendency with temperature rising, making it a good candidate for optical temperature sensors.