Study of the Resonance Energy Transfer Between Two Dye Cations Embedded in Layered Silicates

The Langmuir – Blodgett (LB) method is one of the useful techniques to prepare ultra-thin films with precise organization of embedded dye cations. The main limitations for the preparation of LB films is that the surfactants, building blocks of the LB films, must be amphiphiles and not soluble in water. In our study we used laser dye cation (rhodamine) with long alkyl chain in the structure, which makes this cation sufficiently hydrophobic. The alkylammonium chain helps to prevent dye molecular aggregation. The objective of this study was to prepare LB films built from synthetic saponite particles and adsorbed alkylammonium and organic dye cations. Energy transfer between two dye cations in LB films was studied. Oxazine 4 – energy acceptor molecules - does not represent an amphiphilic molecule, and is soluble in water. This problem we solved using long chain alkylammonium solution as the third component. We found out RET proceeded with high yields. The molecules of rhodamine played the role of molecular antennas absorbing green light (energy donor). Resonance energy transfer was detected as a quenching of light emission from rhodamine (580 nm) in favour of the red light luminescence from oxazine ( 623 nm), playing the role of energy acceptor. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3530

One – and Two-Step Resonance Energy Transfer Between Cyanine Dyes in Layered Silicates Colloidal Systems

Resonance energy transfer (RET) is of high interest for both the basic research and practical applications. It is a phenomenon of radiationless transmission of energy between donor and acceptor molecules. In this study single- and two-step (RET) was investigated between cyanine dye cations (NK1, NK2, NK3) in colloids of layered silicate, synthetic Sumecton saponite. In these systems the dye molecules played role of the energy donors (NK1) or energy acceptors (NK2, NK3) or both (NK2). The adsorption and formation of various types of dye species was studied using visible spectroscopy. The absorption spectroscopy did not detect any significant molecular aggregation of the dyes at the surface of saponite particles. The RET process was described by fluorescence spectroscopy. Both the single- and two-step RET were detected in saponite dispersion. Effects of various parameters on the efficiency of the RET process, such as dye concentrations, saponite properties the distances between co-adsorbed dye cations were found to be essential. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3530