Valiantsin Askirka

The fabrication of nanocomposite photonic materials suggests their use in a wide variety of applications. An essential requirement for such materials is their photostability and high photobleaching resistance. Both lanthanides and quantum dots are good candidates for embedding in the polymer matrix to obtain highly luminescent nanocomposites. This paper presents the concept for the ratiometric optical pulsed laser power sensor based on terbium and red-emitting semiconductor quantum dots co-doped polymer luminescent nanocomposite for application in inexpensive laser monitoring systems. Full Text: PDF References P. Singh, S. Kachhap, P. Singh, S.K. Singh, "Lanthanide-based hybrid nanostructures: Classification, synthesis, optical properties, and multifunctional applications", Coord. Chem. Rev. 472, 214795 (2022). CrossRef X. Peng, Z. Wu, C. Ye, Y. Ding, W. Liu, "Analysis of the Emission Features in CdSe/ZnS Quantum Dot-Doped Polymer Fibers", Photonics 10(3), 327 (2023). CrossRef J.-C.G. Bünzli, "Lanthanide Photonics: Shaping the Nanoworld", Trends Chem. 1(8), 751 (2019). CrossRef A.K. Singh, "Multifunctionality of lanthanide-based luminescent hybrid materials", Coord. Chem. Rev. 455, 214365 (2022). CrossRef O.A. Goryacheva, N.V. Beloglazova, A.M. Vostrikova, M.V. Pozharov, A.M. Sobolev et al., Talanta 164, 377 (2017). CrossRef Lanthanide-to-quantum dot Förster resonance energy transfer (FRET): Application for immunoassay CrossRef M. Cardoso Dos Santos, N. Hildebrandt, "Recent developments in lanthanide-to-quantum dot FRET using time-gated fluorescence detection and photon upconversion", Trends Anal. Chem. 84, 60 (2016). CrossRef M. Valledor, J.C. Campo, F. Ferrero, I. Sánchez-Barragán, J.M. Costa-Fernández, A. Sanz-Medel, "A critical comparison between two different ratiometric techniques for optical luminescence sensing", Sens. Actuators B Chem. 139(1), 237 (2009). CrossRef A.P. Demchenko, "Dual emission and its λ-ratiometric detection in analytical fluorimetry. Pt. I. Basic mechanisms of generating the reporter signal", Methods Appl. Fluoresc. 11(3), 033002 (2023). CrossRef J. Zhou, B. Del Rosal, D. Jaque, S. Uchiyama, D. Jin, "Advances and challenges for fluorescence nanothermometry", Nat. Methods 17(10), 967 (2020). CrossRef Y. Hu, F. Xie, Q. Liu, N. Wang, J. Zhang et al., "Microfabricated sensor device for CW and pulsed laser power measurements", Opt. Expr. 31(2), 2330 (2023). CrossRef V. Askirka, V. Stsiapura, P. Miluski, "Efficient FRET in new co-doped Tb(tmhd)3-CdSe/ZnS quantum dots-poly (methyl methacrylate) polymer nanocomposites for optoelectronic and sensor applications", J. Lumin. 279, 121047 (2025). CrossRef P. Miluski, M. Kochanowicz, J. Zmojda, A. Baranowska, D. Dorosz, "Energy transfer of Tb(tmhd)3 - Rhodamine B in poly(methyl methacrylate) fiber for new photonic applications", Opt. Mater. 87, 132 (2019). CrossRef M. Cardoso Dos Santos, W.R. Algar, I.L. Medintz, N. Hildebrandt, "Quantum dots for Förster Resonance Energy Transfer (FRET)", Trends Anal. Chem. 125, 115819 (2020). CrossRef

In this paper, the relaxation isomerization properties of a spiropyran-doped poly(methyl methacrylate) (PMMA) UV light-responsive dynamic material are presented. The polar liquid (acetonitrile) and solid (PMMA matrix) medium may contain two merocyanine isoforms of the selected spiropyran. A complex equilibrium of the colored and colorless spiropyran isoforms resulted in specific transformations of the absorption spectra during the relaxation process. Bands at 522 nm and 580 nm characterized the absorption of the fabricated dynamic material in the ground (non-activated) state in the visible range. The presence of colored and colorless isoforms of spiropyran incorporated into the PMMA matrix using Raman spectroscopy was revealed. The photosensitive polymer samples were irradiated with a UV LED (365 nm and 390 nm) under various temperatures (0–30 °C). Spectral changes within the relaxation process demonstrated their complex dynamics. Surprisingly, the photodegradation of the dynamic material was estimated at about 25% (using 390 nm) and 7% (using 365 nm) after eight photoswitch cycles for one isoform, and no fatigue after an additional one (using 390 nm) was discovered. The presented light-responsive material is of interest for UV sensors and new hybrid material design.

The spectra of light reflection by plasmonic metal films deposited in vacuum on dielectric substrates and subsequently annealed at high temperatures are investigated. To explain the optical properties of plasmonic films, a theoretical model of a plane-layered metal-dielectric medium is used. One of the layers of such a structure has the dielectric constant of the metal under study, and the second layer has the dielectric constant calculated within the Maxwell-Garnett approximation for a heterogeneous medium consisting of a suspension of metallic nanoellipsoids in air. The introduction of this layer makes it possible to qualitatively take into account the inhomogeneities of the plasmon film surface. It is shown that the developed model allows a number of features in the experimental reflection spectra to be explained.