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Photoluminescent and nonlinear-optical diagnostics of redistribution of CdSe/ZnS quantum dots in liquid-crystal matrix under UV irradiationтезисы доклада
- Авторы: Sokolovskaya O.I., Presnov N.D., Ezhov A.A., Derikov Ya I., Shandryuk G.A., Karpov O.N., Merekalov A.S., Golovan L.A.
- Сборник: ABSTRACTS OF THE INTERNATIONAL CONFERENCE “ADVANCED LASER TECHNOLOGIES”. KAZAN SCIENCE WEEK. KAZAN, SEPTEMBER 22–26, 2025
- Тезисы
- Год издания: 2025
- Место издания: Издательство ФИЦ КазНЦ РАН Казань
- Первая страница: 202
- Аннотация: Embedding semiconductor quantum dots (QDs) into liquid-crystal (LC) matrix allows their spatialdistribution to be controlled, which is of great importance for fabrication of novel light-emitting deviceswith designed QD distribution. Employing LC with embedded chromophores opens possibility to controlLC phase state by means of their photoisomerization activated by ultraviolet (UV) light at temperaturebelow the LC temperature of isotropization. In the LC phase of the matrix QDs tend to leave it and formaggregates, whereas in isotropic phase all QD are homogeneously dissolved in the matrix [1].In this study, azochromophores of extended (EA) or branched (BA) structure (10 wt.%) were usedas isotropization agents for nematic LC. CdSe/ZnS QDs (1 wt.%) were embedded into LC matrix. Themigration of QDs in phase-changing LC matrix was studied with the help of transmission measurement,fluorescent optical microscopy with cw excitation at wavelength of 532 nm and UV photoinduced (365nm) phase transition in LC matrix. UV illuminated region demonstrates isotropization accompaniedby QDs homogeneous distribution was observed, whereas in LC areas QDs are in an aggregated state.Second – and third harmonic (SH, TH) and upconversion luminescence (UC) signals (Cr:forsteritelaser, 1250 nm, 80 fs, 80 MHz, 150 mW) along with transmission signal in crossed polarizers (diodelaser, 780 nm) were measered in nematic LC with the aforementioned azochromophores and QDs. Thetransmission signal demonstrates drastic fall at the temperature of isotropization of LC (62 °C), whereasall nonlinear-optical signals decreases with the temperature increase and reach mininmun at lower temperature (about 55 °C), which possibly indicates additional structural variation inside the LC.Thus, LC phase transition accompanied by QD migration has been demonstrated and optical harmonic and up-conversion signals are markers for these structural changes.This research was funded by the Russian Science Foundation, grant number № 23-19-00246, https://rscf.ru/project/23-19-00246/.[1] M.A. Osipov, M.V. Gorkunov, Nematic liquid crystals doped with nanoparticles: phase behavior and dielectric properties. In: Liquid Crystalswith Nano and Microparticles. (2016).[2] О.I. Sokolovskaya, V.Yu. Nesterov, et al. Diagnostics of ultraviolet-induced isotropic phase transitions in nematic liquid crystal with azochromophore, Liq. Cryst. and their Appl., vol. 25, pp. 90–98 (2025).
- Добавил в систему: Головань Леонид Анатольевич