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0Nanosensor based on carbon dots with anti-Stokes luminescence
S. Burikov1*, K. Laptinskiy1'2' T. Dolenko1
1- Department of Physics, Lomonosov Moscow State University, Leninskie Gory 1/2, 119991 Moscow, Russia
2- Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Leninskie Gory 1/2, 119991
Moscow, Russia
* sergey.burikov@gmail.com
Carbon dots (CD) are a class of nanomaterials characterized by intense and stable luminescence, good dispersibility in water and biocompatibility. Recently, the study of the optical properties of CD has been of great interest. In particular, it was found that CD interact with environmental molecules in suspensions and can act as pH sensors [1]. One of the problems that arise when using CD-based sensors for the diagnostics of biological media and natural waters is the need to solve the problem of separating the contribution of CD luminescence against the background signal of intrinsic luminescence of the medium (autoluminescence).
However, this problem can be eliminated if it is possible to realize excitation of anti-Stokes luminescence when excited by radiation in the red region of the spectrum. In this case, CD luminescence spectrum is shifted to the short-wavelength region with respect to the wavelength of the exciting radiation, while the autoluminescence signal is not excited.
In this study, it is shown that for CD synthesized by the hydrothermal method from citric acid and ethylenediamine, it is possible to implement an anti-Stokes luminescence excitation mode under excitation by nanosecond laser pulses. It is shown that the luminescent properties of such CD in aqueous suspensions can depend on the temperature and pH of the medium, on interaction with ions and molecules present in the medium. Nanosensors of metal ions have been developed on the basis of CD with anti-Stokes luminescence and the accuracy of determining their concentration in solutions has been evaluated.
The research was carried out at the expense of the grant from the Russian Science Foundation № 22-12-00138, https://rscf.ru/en/project/22-12-00138/.
[1] K.A. Laptinskiy, M.Yu. Khmeleva, S.A. Burikov, A.M. Vervald, T.A. Dolenko. Carbon dots with up-conversion luminescence as
pH-sensor. Applied Sciences, 2022, N12, 12006.
