Concentration-dependent spectral rearrange-ment of photoluminescence in the nanocom-posite material “polycarbonate matrix – gold nanostructures – multidomain HTTH dye”

In this work, the thiazole organic multidomain dye HTTH, which exhibits excited state intramolecular proton transfer (ESIPT) phenomenon, is used as a sample to investigate the influence of the component concentration of the “polycarbonate matrix – gold nanostructures – HTTH dye” system on its photoluminescence spectral characteristics. A hypothesis that different forms of the dye, such as enol form (in the ground state) and keto form (after proton transfer), may be involved in Förster resonance energy transfer (FRET) and plasmon resonance energy transfer (PRET) mediated by gold nanostructures was experimentally verified. The concentration dependence and spectral rearrangement in the photoluminescence of the developed thin-film nanocomposite based on gold nanostructures and HTTH with a transverse concentration gradient were demonstrated and explained by the efficiency of FRET and PRET phenomena depending on the system parameters. The ascertained features open up the possibility of additional manipulation of the spectral properties of the system based on ESIPT-exhibiting molecules by optimization of their parameters, particularly the concentration of components.