Luminescent Nanothermometer Operating at Very High TemperatureSensing up to 1000 K with Upconverting Nanoparticles (Yb3+/Tm3+)

• Published in: ACS applied materials & interfaces Vol. 12; no. 39; pp. 43933 - 43941
• Main Authors: Runowski, Marcin, Woźny, Przemysław, Stopikowska, Natalia, Martín, Inocencio R, Lavín, Víctor, Lis, Stefan
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 30.09.2020
• Subjects: Functional Inorganic Materials and Devices; luminescent nanomaterials; lanthanide ions; optical sensors; extreme conditions; thermally and non-thermally coupled levels; luminescence thermometry
• ISSN: 1944-8244; 1944-8252; 1944-8252
• DOI: 10.1021/acsami.0c13011

Lanthanide-based luminescent nanothermometers play a crucial role in optical temperature determination. However, because of the strong thermal quenching of the luminescence, as well as the deterioration of their sensitivity and resolution with temperature elevation, they can operate in a relatively low-temperature range, usually from cryogenic to ≈800 K. In this work, we show how to overcome these limitations and monitor very high-temperature values, with high sensitivity (≈2.1% K–1) and good thermal resolution (≈1.4 K) at around 1000 K. As an optical probe of temperature, we chose upconverting Yb3+–Tm3+ codoped YVO4 nanoparticles. For ratiometric sensing in the low-temperature range, we used the relative intensities of the Tm3+ emissions associated with the 3F2,3 and 3H4 thermally coupled levels, that is, 3F2,3 → 3H6/3H4 → 3H6 (700/800 nm) band intensity ratio. In order to improve sensitivity and resolution in the high-temperature range, we used the 940/800 nm band intensity ratio of the nonthermally coupled levels of Yb3+ (2F5/2 → 2F7/2) and Tm3+ (3H4 → 3H6). These NIR bands are very intense, even at extreme temperature values, and their intensity ratio changes significantly, allowing accurate temperature sensing with high thermal and spatial resolutions. The results presented in this work may be particularly important for industrial applications, such as metallurgy, catalysis, high-temperature synthesis, materials processing and engineering, and so forth, which require rapid, contactless temperature monitoring at extreme conditions.