Application of nanoluminophores based on NaYF4:Yb3+/Tm3+ complexes as temperature sensors

Abstract

The method of luminescent thermometry in the study of biological objects is now widely used. However, there is a problem that significantly hinders progress in this field. It is related to the fact that when luminescence is excited in the visible range, signal of autoluminescence is always present in the optical spectrum of real biological media. Autoluminescence overlaps with photoluminescence spectrum of most thermosensors based on nanoparticles.
One of the most effective ways to eliminate this problem is using luminescent complexes based on rare earth elements (REE) as temperature sensors. In these complexes, it is possible to implement an anti-stokes (upconversion) luminescence excitation mode when a signal is excited in the near-infrared range. In this case, the autoluminescence signal of biological medium is not excited. The luminescent response of such complexes depends on temperature, which makes it possible to use them as thermosensors.
In this work, NaYF4:Yb3+/Tm3+ nanocomplexes with upconversion luminescence were used as sensor of the local temperature of medium. The medium was probed through a receiving and transmitting fiber cable. To determine the temperature, the dependences of the parameters of the kinetic curves of luminescence decay under excitation by intense nanosecond laser radiation at a wavelength of 975 nm, as well as the ratio of the intensities of the luminescence bands of thermally coupled levels, were used. The proposed method has been tested on various biological media, including water, blood plasma, and muscle tissue.
The study was supported by the Russian Science Foundation grant No. 25-22-00411: https://rscf.ru/en/project/25-22-00411

Speaker

Kirill Alexandrovich Buzanov
Faculty of Physics, Lomonosov Moscow State University
Russia

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