Registration Number
0223U003717,
0122U201741
, R & D reports
Title
Mechanisms of control of luminescent and redox properties in oxide nanocrystals with ions of variable valence
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Head
Seminko Vladyslav V., Доктор фізико-математичних наук
Registration Date
19-06-2023
Organization
Seminko Vladyslav V.
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During realization of the project stable colloidal solutions of REO2-x (RE = Ce, Tb, Eu, Y) nanocrystals with sizes of 2 and 10 nm were obtained and the possibility of controlling their luminescent, sensor and antioxidant properties by varying the size of nanocrystals, type and concentration of impurity ions, redox properties of the environment, as well as the presence or absence of long-term UV irradiation was shown. Using the methods of luminescence spectroscopy, the influence of the presence of oxidants and UV radiation on the dynamics of the incorporation of impurity RE ions into undoped cerium oxide nanocrystals during cation exchange in aqueous solutions, and, as a result, on the optical properties of the obtained nanocrystals, was shown. It was determined that the obtained colloidal nanoparticles provide effective detection of reactive oxygen species (in particular, hydrogen peroxide) by quenching Ce3+ luminescence (as a result of oxidation of Ce3+→Ce4+ ions), as well as Eu3+ and Tb3+ luminescence (as a result of energy transfer from Eu3+ and Tb3+ ions to hydroxyl groups). It was shown that ROS luminescent sensors based on nanoparticles are reversible, and the recovery rate of the luminescent signal increases markedly with increasing temperature, as well as in the presence of continuous UV irradiation (325 nm). The influence of impurity ions on the antioxidant properties of nanocrystals was studied, it was found that the addition of RE3+ ions generally worsens the antioxidant properties of CeO2-x NPs, reducing the rate of decomposition of hydrogen peroxide and increasing the content of hydroxyl radicals formed during the decomposition of peroxide. At the same time, a significant decrease in the concentration of hydroxyl radicals in the presence of TbO2-x nanocrystals was shown, which indicates the antiradical properties of these nanocrystals, which are comparable to the antiradical properties of CeO2-x nanocrystals making them promising for further uses
Product Description
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Seminko Vladyslav V.
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2023-06-19
