Low threshold photon avalanche upconversion emission for temperature sensing based on Yb(III)/Er(III) Co-doped NdVO4 with sphere 3D self-assembled structure microparticles

Abstract

Upconversion luminescent microcrystals (UCMs) due to their optical characteristics have been applicated in temperature detecting fields. However, the accuracy of traditional temperature probes based on UCMs is limited by the low intensity of upconversion luminescence (UCL). Herein, Yb3+ and Er3+ ions co-doped NdVO4 (NdVO4:Yb/Er) UCMs with a 3D self-assembled structure were designed via a hydrothermal method. This innovative structure enables the realization of a photon avalanche (PA) emission process. The Yb3+ and Er3+ co-doping in NdVO4:Yb/Er UCMs significantly reduces the PA threshold compared to NdVO4:Er UCMs. Obvious PA process produced by Yb3+/Er3+ doping is observed at low excitation threshold (～13 mW) in NdVO4:Yb/Er UCMs, enhancing the whole UCL intensity. Additionally, the NdVO4:Yb/Er UCMs exhibit a high temperature sensitivity of 3.5% K−1 at low pump power, indicating that UCMs have the potential application in optical temperature sensor.