Amplified spontaneous emission of glass forming DCM derivatives in PMMA films

Abstract

4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran (DCM) is well known red laser dye which can be used also in solid state organic lasers. The lowest threshold value of amplified spontaneous emission was achieved by doping 2wt% of DCM molecule in tris-(8-hydroxy quinoline) aluminium (Alq 3 ) matrix. Further increase of dye concentration also increases threshold value. It is due to large intermolecular interaction which reduce photoluminescence quantum yield. Compounds with small intermolecular interaction and which exhibit similar amplified spontaneous properties as DCM could be useful for solid state organic lasers.In the work photoluminescence and amplified spontaneous emission properties of two DCM derivatives in poly(methyl methacrylate) (PMMA) matrix were investigated. Bulky trityloxyethyl groups are attached to the donor part of investigated molecules. These groups reduce intermolecular distance wherewith reduce photoluminescence quenching. More than one order of magnitude lower excitation threshold energy of the amplified spontaneous emission was achieved in doped polymer films with investigated compound in comparison to doped polymer with DCM. It means that the investigated compound is more perspective as a laser material compared to previously study.