Enhanced Fluorescence in Stilbene-Based Photoluminescent Materials: Host-Guest Systems and Förster Resonance Energy Transfer for Far-Red and White-Light Emission

abstract

English

Organic conjugated molecules have garnered significant attention over the past decades due to their unique optical properties, tuneable colours, and versatile applications. In this study emphasis will be placed on the characterization of stilbene-based photoluminescence materials and their properties in solid-state and molecular mixtures. Fluorescence properties of studied materials primarily come from an intramolecular electronic transition of charge-transfer (CT) character. With this approach it is possible to design materials with wide range of colour emission. In case of red-emitting materials, such approach leads to narrowing the band-gap and reduction of solid-state fluorescence quantum yields due to the promotion of intramolecular non-radiative processes. To improve fluorescence in far-red (FR) part of spectrum so-called host-guest systems (HG) can be utilized. HG systems are binary mixtures of structurally similar molecules with different band gab energies resulting in different colour of emitted light. In such systems the effect of Förster resonance energy transfer (FRET) between two components of a mixture, where one acts as donor of energy and other as acceptor of energy, increases the fluorescence quantum yield of an acceptor fluorophore beyond its usual level. Such systems are deployed in the form of nanoparticles, showing increased intensity of acceptor-like photoluminescence. If the donor-acceptor pair of molecules and their ratio is carefully selected it is possible to achieve only partial energy transfer leading to creation of systems in which the emission of both components persists. With this approach it is possible to obtain bright with-light emitting (WLE) materials. Intense solid-state fluorescence materials are highly desirable for various applications. WLE materials are used in light-emitting field-effect transistors or organic light-emitting diodes (OLEDs) where the basis consists of white-light emitting layer. FR emitting materials are especially important in form of water-dispersible nanoparticles for bioimaging. By utilizing these materials, fluorescence imaging benefits from decreased self-fluorescence in the FR region; the impact of light scattering is reduced, thus the far-red fluorescence is much less affected. Moreover, red light demonstrates higher penetrability in biological tissue. This allows for higher optical contrast and reduced photodamage.

Photoluminescence, Host-guest (HG) systems, Förster resonance energy transfer (FRET), White-light emitting (WLE) materials, Far-red (FR) fluorescence

SMOLKA, R.; KOLAŘÍKOVÁ, A.; ČEKAL, J.; PAUK, K.; STANISLAV, L. Jr.; IMRAMOVSKÝ, A.; VALA, M.

12. 9. 2024

Vysoké učení technické v Brně, Fakulta chemická, Purkyňova 464/118, 612 00 Brno

Brno

99

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https://www.fch.vut.cz/chl/konference/program/bookofabstracts-pdf-p269547