Multimodal temperature sensing using Zn2GeO4:Mn2+ phosphor as highly sensitive luminescent thermometer

Abstract

Motivated from increasing demands of non-contact temperature sensing, here Mn2+ doped Zn2GeO4 (ZGO) phosphor is produced to explore the temperature dependencies of its optical characteristics. Temperature dependencies of emission intensity and luminescence decay lifetime of Mn2+ in the range from 250 K to 420 K are investigated. The maximum relative sensitivities achieved are 4.5% K−1 and 4.6% K−1 for temperature sensing modes of emission intensity and decay lifetime, respectively. In order to realize temperature imaging, a temperature sensing scheme is employed based on time-resolved technique with the help of an intensified charge coupled device (ICCD) and a fluorescent microscope, where the luminescence integral intensities ratio of obtained images for two time segments is calibrated to measure the temperature. A maximum relative sensitivity of 12.2% K−1 is achieved and the best temperature resolution is about 0.68 K. Employing the temperature imaging system we built, the temperature distribution of micro circuit on a printed circuit board (PCB) has been monitored with high temperature and spatial resolution. The results may offer a significant advance in the development of temperature visualization for precise distributions and change of temperature field.