Thermal history forensics using the emission intensity ratio of YVO4:Eu3+ phosphor.

[Display omitted] • Self-referenced thermal history forensics is demonstrated with Eu3+:YVO 4 luminescence. • Ratio of Eu3+ 5D 0 →7F 2 and 5D 0 -7F 1 emissions strongly depends on the phosphor size. • Thermal history imaging is demonstrated over the 400 – 900 °C range. • Thermal history reading does not depend on the duration of temperature exposure. We demonstrate the thermal history forensic measurements founded on the emission intensity ratio of Eu3+-doped yttrium vanadate. An increase in phosphor's crystallite size with annealing temperature is observed, causing a significant and permanent increase in the emission intensity and symmetry ratio (ratio of Eu3+ 5D 0 → 7F 1 and 5D 0 → 7F 2 emissions). This ratio is used as a forensic indicator of the maximal temperature to which phosphor was exposed. Additionally, we demonstrated that irreversible change in the symmetry ratio after exposure to high temperatures is insensitive to the exposure time. Finally, it is shown that thermal history readings can be performed at any temperature. The applicative potential of the proposed approach was confirmed in the proof-of-concept experiment on a steel plate covered with phosphor and exposed to high temperatures. [ABSTRACT FROM AUTHOR]