During the last two decades, small organic molecules have been widely studied for potential applications in organic solid-state lasers due to low-cost production, simple processing possibility and physical property tuning ability through chemical structure synthetic modifications. One of the most investigated and applied compound in dye lasers is 4- (dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran (DCM). It has shown remarkable properties as a dye in solid-state lasers. One of the drawbacks of this compound is high intermolecular interactions which reduce emission efficiency. Therefore it can be applied only in doped systems in low concentration (around 2 wt%). Recently we have demonstrated that incorporation of bulky triphenyl groups in the low molecular mass organic compounds enables the ability to form good optical quality transparent glassy films by solution processing. Additional such bulky groups reduce intermolecular interaction thus increase photoluminescence quantum yield in the thin film. In the presentation, we will show optical properties of new 2-cyanoacetic derivatives where two different bulky groups (9H-carbazole fragment and triphenyl group) are attached to molecule electron donating and accepting parts. Synthesized compounds have light absorption from 400nm to 600nm and photoluminescence from 600 nm up to 800 nm. Dyes with only one incorporated electron donating fragment showed 16% PLQY and ASE excitation threshold values (below 52 μJ/cm<sup>2</sup>) in neat thin films. Two electron donating fragment containing molecules have PLQY of 7% and ASE excitation threshold 223 μJ/cm<sup>2</sup>.
In this work photoluminescence and amplified spontaneous emission properties of new original 2-cyanoacetic acid derivative in different concentration mixed in polyvinyl carbazole (PVK) matrix were investigated. Ethyl 2-(2-(4-(bis(2- (trityloxy)ethyl)amino)styryl)-6-tert-butyl-4H-pyran-4-ylidene)-2-cyanoacetate (KTB) is recently synthesised nonsymmetric red light emitting laser dye, that in previous experiments with neat thin films showed low amplified spontaneous emission (ASE) threshold value. Based on PVK high refractive index it has been used as a polymer to ensure the preparation of good planar waveguide. Luminescence quenching is expected in neat amorphous thin films according to previous experiments which reduces photoluminescence quantum yield and increases ASE excitation threshold energy. It could be overcome by a decrease of the intermolecular interactions between laser active molecules by doping them in polymer matrix thereby decreasing photoluminescence quenching effect in the system by increasing distance between organic molecules which in turn results in lowering ASE excitation threshold energy. The lowest threshold value of ASE was achieved at 20wt% of KTB molecule in PVK matrix. Ability to significantly decrease intermolecular interactions and excitation threshold energy of investigated compound in host-guest systems makes it promising to be used as a laser dye in preparation of organic solid state lasers.