Investigation of photoluminescence and amplified spontaneous emission properties of cyanoacetic acid derivative (KTB) in PVK amorphous thin films

Abstract

In this work photoluminescence and amplified spontaneous emission properties of new original 2-cyanoacetic acid derivative mixed in polyvinyl carbazole (PVK) matrix at different concentration 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 good planar waveguide structure. According to the previous experiments luminescence quenching is expected in neat amorphous thin films which reduces photoluminescence quantum yield and increases ASE excitation threshold energy. It could be overcome by doping the laser active molecules in polymer matrix. The lowest threshold value of ASE was achieved at 20wt% of KTB molecules in PVK matrix. Ability to significantly decrease intermolecular interactions and excitation threshold energy of investigated compound in the host-guest systems makes KTB promising to be used as a laser dye in preparation of organic solid state lasers.