Photo-physical and lasing characterization of an aromatic diamine-xylylene copolymer

A solution processable poly-condensation product of high glass transition temperature containing 50 mol% electrically active triphenylamine dimer (TPD) chromophores and 50 mol% non-conjugated α,α-diphenylxylylene (DPX) units in the main chain is studied for its photo-physical and lasing properties. This copolymer abbreviated as poly-TPD-DPX shows travelling-wave laser action (amplification of spontaneous emission) as neat film on a fused silica substrate and in liquid solution when transversally pumped with picosecond excitation pulses (wavelength 347.15 nm, duration 35 ps). Lasing occurs at 419 nm for the neat film and at 405 nm for the polymer in 1,4-dioxane solution. The optical constants (absorption spectrum and refractive index spectrum) of the neat film are determined by reflection and transmission measurement. The absorption cross-section spectra and fluorescence quantum distribution spectra of neat films and 1,4-dioxane solutions are compared. The fluorescence quantum yields of poly-TPD-DPX neat films and 1,4-dioxane solutions are 0.16 and 0.66, respectively.