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Organic solids can be used as emitters in organic solid-state lasers. As one of the most popular red light-emitting organic laser dyes is DCM that has been widely used in a dye laser. It has been used in solid-state lasers. The active material was host-guest systems where DCM was doped at low concentration due to large intermolecular interactions. We previously developed original glass-forming DCM derivatives were attached bulky triphenyl groups reduced intermolecular interaction thus it was possible to observe amplified spontaneous emission (ASE) in the neat films.
In this work, we are presenting new derivatives with modified electron acceptor and donor groups. The investigated compounds are pyranyliden derivatives with malononitrile and 1H-indene-1,3(2H)-dione as acceptor and bis(5,5,5-triphenylpentyl)amino- and 5,5,5-triphenylpentyl-piperazin-1-yl- as donor. Photoluminescence and ASE were investigated in thin films. All compounds emit light in red spectral regain with the photoluminescence quantum yield of up to 6%. Amplified spontaneous emission excitation threshold energy was about 100 μJ/cm2.
Silver nanoparticles were used to increase the performance of the compounds. Triangular nanoparticles with the surface plasmon resonance (SPR) overlapping the absorption and emission spectra of compounds were used. Metal nanoparticles were dissolved in the organic solution with investigated compounds. The solution was ultrasonicated prior to deposition on a glass substrate by the spin-coating method.
SPR enhance the absorption and emission of the investigated compounds. Accordingly, it was observed as at least two times increase in the PLQY of mixed thin films and more than two times were decreased excitation threshold energy of ASE. More detailed results and metal nanoparticle influence on emission properties of investigated compounds will be discussed.
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