Luminescent thermometry at a new level. Widening the temperature range of luminescent thermometers through the intra- and interconfigurational transitions of Pr3+

Significance 

Different applications in nearly all fields require measurement of temperatures for various process analysis and controlling. Among the available temperature measurements methods, a pyrometer is a commonly used device. It determines the temperature of a medium based on the emitted thermal radiation. However, recent advances in technology have seen numerous improvements in not only pyrometers but also develop other methods for measuring temperatures.

Non-contact temperature measurements like radiation pyrometry are widely preferred over electrical contact methods. This is due to their excellent properties such as high upper-temperature limit, immunity to the surrounding environment and high response rate. Unfortunately, pyrometry experiences several limitations including flame interference and sensitivity to stray light that results in errors thus reducing their operational efficiency. As such, researchers have been looking for alternatives for overcoming the disadvantages of pyrometry and have identified luminescence thermometry as a promising solution. This, in particular, has attracted significant attention owing to its excellent properties including insensitive nature to electromagnetic interferences.

Currently, emerging technologies in the fields of biomedicine, photonics among others requires the use of non-contact and accurate temperature sensors. This required development of more efficient temperature sensors to meet the demands of accuracy, broad sensing range and thermal sensitivity. Despite studying several luminescent phosphors, it has been difficult to find a single composition with the potential for obtaining desired thermal sensitivity and accuracy in a wide temperature range. For instance, a narrow temperature range is a drawback for most of the available luminescent phosphorous materials.

Recently, a group of researchers led by Professor Luís António Dias Carlos at the University of Aveiro and Professor Eugeniusz Zych at University of Wroclaw exploited the possibility of widening the temperature range of luminescent thermometers. Briefly, the authors combined the intra-and interconfigurational transitions of the Pr3+ ion in a single material while using Sr2GeO4:Pr3+ for illustration. They purposed to enhance the performance of the sensor by implementing the luminescence thermometry in a broad temperature range and relatively high thermal sensitivity. Their work is published in the research journal, Advanced Optical Materials.

The authors observed that it was possible to widen the temperature range of the luminescent thermometers. For instance, the broadest temperature in the range of 16-600K was noted. Consequently, the overall performance of the sensor was significantly increased with a maximum relative sensitivity of up to 9.0%, 0.6% and 0.5% for the cryogenic range, physiological range and high-temperature range were noted. Moreover, the minimum temperature uncertainty of 0.1K was noted. Furthermore, the thermometer remained three times as effective in high temperatures as compared to the conventional infrared thermographic systems thus confirming their efficiency in offering high-temperature range measurements.

The study is the first to cover such a broad temperature range. Thus, they successfully demonstrated that the inter- and intraconfigurational of Pr3+ transitions are effective for widening the temperature range of luminescent thermometers. Therefore, the study will advance the fabrication of high-performance temperature sensors with desired properties to meet the increasing demand for various application in different fields.

About the author

Eugeniusz Zych is Full Professor and head of Luminescent Materials Group in the Faculty of Chemistry at University of Wroclaw, Poland. His main research interest includes energy storage and persistent luminescence phosphors, X-ray phosphors and scintillators and luminescent thermometers.

In his research he is dedicated to design materials properties by compositional and technological approaches deliberately applied. He published around 150 papers and a few book chapters. He is associate editor of Optical Materials and Optical Materials: X, member of Electrochemical Society and member of the Executive Committee of the Luminescence and Display Materials, Electrochemical Society.

About the author

Luís António Dias Carlos is Full Professor in the Department of Physics at the University of Aveiro and vice-director of the CICECO-Aveiro Institute of Materials, Portugal. He is member of the Lisbon Academy of Sciences and of the Brazilian Academy of Sciences.

His current research interests include luminescent nanothermometers, luminescent solar concentrators, and organic-inorganic hybrids for green photonics (solid-state lighting and integrated optics). He published around 424 papers and 4 international patents and was co-guest editor of a RSC book on Nanoscale Thermometry and special issues of the J. Sol-Gel Science & Technology (2010) and J. Luminescence (2015 and 2018).

He is editor of Physica B – Condensed Matter, specialty chief editor of Frontiers in Chemistry (Inorganic Chemistry), associate editor of the Journal of Luminescence and member of the editorial board of the J. Coordination Chemistry, J. Sol-Gel Science & Technology and J. Rare Earths.

Reference

Brites, C., Fiaczyk, K., Ramalho, J., Sójka, M., Carlos, L., & Zych, E. (2018). Widening the Temperature Range of Luminescent Thermometers through the Intra- and Interconfigurational Transitions of Pr3+. Advanced Optical Materials, 6(10), 1701318.

Go To Advanced Optical Materials

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