Concentration - dependent fluorescence properties of Nile Red in TiO2 based thin films

• Published in: Journal of molecular liquids Vol. 306; p. 112899
• Main Authors: Synak, Anna, Bojarski, Piotr, Grobelna, Beata, Kułak, Leszek, Szczepańska, Elżbieta, Mońka, Michał
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.05.2020
• ISSN: 0167-7322; 1873-3166
• DOI: 10.1016/j.molliq.2020.112899

Thin films of Nile Red in TiO2 matrix were prepared with the sol–gel method for different dye concentrations. It was found that at high dye concentration fluorescence and absorption spectra as well as fluorescence intensity decay and time-resolved fluorescence spectra exhibit strong changes. In particular, fluorescence spectra profiles are strongly shifted to the red in a way typical of aggregate formation. Fluorescence intensity decays much faster with increase in concentration in the monomer band due to Nile Red aggregate formation and excitation energy trapping. Time-resolved fluorescence spectra exhibit strong evolution. Clear formation of aggregate band at the red part of time-resolved emission spectra was observed. •Thin films of Nile Red in TiO2 matrix were prepared with the sol–gel method for different dye concentrations.•NR in TiO2 thin films forms the H and J aggregates in the ground state.•J aggregates of NR occurred fluorescent.•Efficient energy transfer from NR monomers to aggregates was observed.