Optical fibre thermometry using ratiometric green emission of an upconverting nanoparticle- polydimethylsiloxane composite

Kumar, Rahul; Binetti, Leonardo; Nguyen, .T Hien; Alwis, Lourdes S.M.; Sun, Tong; Grattan, Kenneth T.V.

Abstract

The thermally coupled green band emission from excited Er 3+ ions has been used in the past to create optical thermometers, by doping the material in various types of media, particularly glasses. Glasses are known to be excellent hosts for Er 3+ ions: however, high temperatures (>900 K) are usually required for doping these ions into glasses and a non-linear temperature response is often produced. In this work, the frequently encountered drawbacks of glass-based temperature sensors have been addressed by developing a temperature sensor created at a lower temperature (543 K), by dip-coating chemically synthesized upconverting nanoparticles (UCNP-NaYF4:(18%) Yb 3+ , (2%) Er 3+) embedded in polydimethylsiloxane (PDMS) onto the tip of a 1000 μm optical fibre, to create the actual fibre probe. The sensor shows an excellent linear response (R 2 = 0.991) over a very useful temperature range of 295 K-473 K, with a sensitivity of 2.9 ×10-3 K-1 , a temperature resolution of ± 2.7 K and response time of ~ 5 seconds. Additionally, a probe was investigated 2 where a pure upconverting nanoparticle powder was coated on the tip of optical fibre and its spectral and temperature response was obtained (and cross compared with that of UCNP-PDMS composite). The results obtained from the probe development work show that the UCNP-PDMS-coated optical fibre temperature sensor developed offers a better alternative to more conventional Er 3+ doped glass-based temperature sensors, in terms of the thermal budget, the synthesis process and the ease of coating, creating as a result, a very linear device response.

Citation

Kumar, R., Binetti, L., Nguyen, .. H., Alwis, L. S., Sun, T., & Grattan, K. T. (2020). Optical fibre thermometry using ratiometric green emission of an upconverting nanoparticle- polydimethylsiloxane composite. Sensors and Actuators A: Physical, 312, Article 112083. https://doi.org/10.1016/j.sna.2020.112083

• Journal Article Type: Article
• Acceptance Date: May 16, 2020
• Online Publication Date: May 21, 2020
• Publication Date: 2020-09
• Deposit Date: May 18, 2020
• Publicly Available Date: May 22, 2021
• Print ISSN: 0924-4247
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 312
• Article Number: 112083
• DOI: https://doi.org/10.1016/j.sna.2020.112083
• Keywords: Upconverting Nanoparticle; Polydimethylsiloxane; Optical temperature sensor; Optical Fibre; Organic-inorganic hybrid
• Public URL: http://researchrepository.napier.ac.uk/Output/2663823