Molecular Design of FR/NIR Emitting Materials for Bioimaging and Utilization of Host-Guest Interactions as a Way of Increasing Fluorescence Intensity

abstract

English

The intense solid-state fluorescence (SSF) is desirable for light-emitting field-effect transistors, organic light- emitting diodes (OLEDs), or water-dispersible nanoparticles for bioimaging. In this study, emphasis will be placed on the characterization of photoluminescence materials and their potential use as nanoparticles for in vivo bioimaging. By utilizing FR/NIR emitting materials, fluorescence imaging benefits from decreased self-fluorescence and the reduction of light scattering. In this study, to obtain NIR fluorescence, an intramolecular electronic transition of charge-transfer (CT) character is utilized. Unfortunately, such systems result in narrow band-gap organic materials and inevitably lead to reduced solid-state fluorescence quantum yields due to the promotion of intramolecular non-radiative processes. To overcome this, reduction of exciton migration via self-trapping is pursued. Crystal engineering methods are used to achieve either excimer-type NIR fluorescence or utilize so-called host-guest systems (HG), in which the effect of resonance energy transfer increases the solid-state fluorescence quantum yield of a fluorophore beyond its usual level. Such systems are deployed in the form of nanoparticles, showing increased QY of new π-conjugated fluorescent molecules based on derivates of DPA-DPS-EWG, such as DPA-DPS-IOO from 5 % to 14 % at 693 nm. This demonstrates the potential of such an approach as a way of obtaining nanoparticles with increased fluorescence intensity in the FR/NIR region, which is desirable for their application in NIR bioimaging.

FR/NIR fluorescence, nanoparticles, host-guest mixtures, charge-transfer electronic transitions, bioimaging

SMOLKA, R.; KOLAŘÍKOVÁ, A.; LUŇÁK, S.; VALA, M.; IMRAMOVSKÝ, A.; PAUK, K.

27. 8. 2023

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