AMPLIFICATION OF ORGANIC SEMICONDUCTOR LUMINESCENCE IN THIN FILMS WITH SILVER NANOPARTICLES

The luminescence of organic semiconductors can be enhanced by surface plasmon resonance on metal nanoparticles, so it can pave the way for the development of light modulators or laboratory chips. Silver nanoparticles are twodimensional plasmonic nanostructures that have attracted massive attention due to their strong shape-dependent related applications and optical properties. When the lateral dimension of silver nanoplates is much larger than the thickness, they possess a very great degree of anisotropy, which favors a high tunability of their localized surface plasmon resonance and maximum electromagnetic-field enhancement therefore is generated. Within this work, silver nanoparticles of different sizes were obtained in aqueous solution, which were stabilized with sodium citrate and PVP (Polyvinylpyrrolidone). Most luminophores are insoluble in water, so nanoparticles had to be transferred to the organic environment. This was achieved using the ultrasonic method. The obtained nanoparticle solutions were added to organic luminophore DWK-1-TB solution. Before nanoparticles were applied to thin films together with organic luminophore (DWK-1-TB), their properties (quantum yield, emission) were studied. Thin films were coated from these solutions using spin coating method. Different concentrations of silver nanoparticles solutions were coated, as well as films of different thickness. PMMA (polymethyl methacrylate) was added because the nanoparticles efficiently transfer into the PMMA solution and its presence at low concentrations improves the homogeneity of the thin film. Quantum yield, change in luminescence depending on the type of nanoparticles, as well as film thickness were studied in the obtained samples.