The influence of dopant concentration and grain size on the ability for temperature sensing using nanocrystalline MgAl2O4:Co2+,Nd3+ luminescent thermometers

Abstract

In this work, for the first time, the ability of nanocrystalline MgAl₂O₄:Co²⁺ and MgAl₂O₄:Co²⁺,Nd³⁺ phosphors for temperature sensing was investigated in a wide temperature range. It has been proved that the emission intensity of Co²⁺ can be modulated either by its concentration or by the size of nanocrystals. The highest relative sensitivity was obtained for MgAl₂O₄:0.01% Co²⁺,5% Nd³⁺ annealed at 1100 °C (about 0.3% °C⁻¹). The provided analysis reveals that Co²⁺ and Nd³⁺ are located in tetrahedral sites of Mg²⁺ ions. The presented results show that Co²⁺ luminescence depends on temperature changes of its environment, and it is found that nanothermometers doped with Co²⁺ could be a potential temperature sensors in luminescent thermometry.