Characterization of Ce:CSSO, Pr:CSSO, and co-doped Ce,Pr:CSSO phosphors for aerosol phosphor thermometry

Abstract

The phosphor Ce:Ca3Sc2Si3O12(Ce:CSSO) was recently investigated for aerosol phosphor thermometry (APT) and shown to be capable of temperature imaging up to at least 1400 K. To date, no thorough characterization of the temperature dependent emission properties of the phosphor has been performed up to 1400 K. Additionally, due to limited sensitivity over certain temperature ranges continuous temperature imaging from 300 to 1400 K was not possible. Here, cerium and praseodymium doped into CSSO are investigated to address these limitations. Singly-doped Ce:CSSO and Pr:CSSO, and co-doped Ce,Pr:CSSO phosphor samples were studied. Emission lifetimes and quenching behavior were characterized in a tube furnace for each phosphor. Results from the singly-doped phosphors were used to interpret the co-doped phosphor results. The phosphor characterization data was used to estimate thermometry performance at temperatures relevant to low-temperature ignition studies in engines. The proposed diagnostic uses a combination of co-doped APT, host-referenced APT, and scattering-referenced APT approaches to increase the range over which high-precision temperature measurements can be made. Characterization results include the first reported measurements of luminescence lifetimes for Ce:CSSO and Pr:CSSO at temperatures up to 1400 K, and the highest reported quenching temperature for a phosphor using 4f5d emission (1230 K for Ce:CSSO). Furnace measurements showed a normalized temperature-sensitivity of > 0.25 % K−1 from room temperature to 1400 K for at least one diagnostic approach using the co-doped Ce,Pr:CSSO phosphor. Estimates suggest that the co-doped Ce,Pr:CSSO phosphor is feasible for APT at temperatures ranging from 300 to 925 K and 1030 to at least 1400 K, with better than 40-K single-shot precision. The performance of Ce:CSSO and Ce,Pr:CSSO are similar throughout the investigated temperature range.

A summary of new developments in phosphor thermometry

“…Some of these developments are showcased in this special feature of Measurement Science and Technology which contains seven papers that were presented at ICPT 2020. Two papers report on new phosphors and thermometry methods which function at very different temperature ranges: 10-350 K, useful for studies of cryogenic and physiological systems [8]; and up to 1400 K for the study of intermediate-temperature reacting gas flows [9]. Both studies are fine examples of selecting host-dopant combinations to tailor the luminescence characteristics for the application of interest based on an understanding of the material electronic structure and properties.…”