EFFECT OF SILVER NANOPARTICLES ON ENERGY TRANSFER EFFICIENCY IN DONOR-ACCEPTOR MIXTURES OF ORGANIC DYES: IMPROVEMENT OF ACTIVE MEDIA FOR LUMINISCENT TECHNOLOGIES

Subject and Purpose. The paper presents research into the effect of silver nanoparticles on the efficiency of excitation energy transfer in donor-acceptor mixtures of organic dyes. These mixtures make active media in luminescent solar concentrators and luminescent transformers. Our concern is to explore the possibility of boosting the excitation energy transfer in these media by adding plasmonic nanoparticles. The discussion centers on our experimental studies involving two donor-acceptor dye combinations: Coumarin 314 with Rhodamine 6G, and 3-Methoxybenzanthrone with Sulforhodamine 101, while varying acceptor dye concentrations. Methods and Methodology. The spectral-luminescent characteristics of aqueous-ethanolic solutions of both individual dyes and their mixtures are measured with and without silver nanoparticles synthesized by the citrate reduction method. Based on the spectral measurements, the energy transfer parameters for each donor-acceptor pair are calculated, and excitation en- ergy transfer efficiencies in the samples with and without nanoparticles are assessed. Results. It has been revealed that adding nanoparticles to the mixture improves the excitation energy transfer efficiency between donor-acceptor molecules, which is equivalent to increasing the critical transfer radius. It has been found that the factor causing the growth of the critical radius is independent of the concentration of acceptor dye molecules. So, the efficiency of excitation energy transfer in the examined nanocomposites is governed, first of all, by the interaction between donor molecules and plasmons of nanoparticles. Conclusions. Adding plasmonic nanoparticles to multicomponent dye-based active media enhances the efficiency of excitation energy transfer between molecules of donor-acceptor pairs. This enhancement occurs because localized surface plasmons provide an additional channel of energy transfer. The main factor to improve this energy transfer efficiency is the donor-plasmon interaction. Consequently, the development of nanocomposite media can be optimized through appropriate combinations of dyes and nanoparticles.