American Chemical Society
an3c03948_si_001.pdf (5.19 MB)

Er3+-Doped Upconversion Nanoparticle Coatings for Thermometric Microscanning: Tackling Experimental Factors

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journal contribution
posted on 2023-11-03, 17:34 authored by Alfredo M. Aguilar, Ezequiel L. Saidman, María V. Rosato-Siri, Luciano Marpegán, Eduardo D. Martínez
The generation and flow of heat in the microscale are involved in a great variety of physical, chemical, and biological processes. Accurate measurement of local temperatures provides essential information for the complete characterization of nano/microdevices and the comprehension of local thermal effects. Using Er3+-doped upconversion nanoparticles (UCNPs) as thermal probes deposited on different thermally active microstructures, we assembled a motorized platform for scanning the upconversion luminescence (UCL) and retrieved temperature readings. We discuss critical aspects of the technique, such as calibration procedures, self-heating of substrate materials, the role of power density of the excitation light, and the uniformity of the coatings. A temperature resolution of 0.24(2) K, a spatial resolution of 0.24(7) μm, and a temporal resolution of 0.034(6) s were achieved. The platform was used for the characterization of two thermally active systems of interest: a microheater device and a photothermal nanoparticle coating immersed in a buffered solution. We emphasize potential applications for this method in the fields of cell biology and explore potential improvements with the use of UCNPs with increased thermal sensitivity, uniform self-assembled monolayer covering, and the integration of specific optical elements in the setup.