Travelling-wave lasing of TPD solutions and neat films

The travelling-wave lasing action (amplified spontaneous emission (ASE)) of the electrically active triphenylamine dimer N,N′-diphenyl-bis(3-methylphenyl)-biphenyl-4,4′-diamine (TPD) in 1,4-dioxane solution and as neat film is studied. The samples are transversally pumped with picosecond excitation pulses (wavelength, 347.15 nm; duration, 35 ps). Lasing occurs at 401 nm for TPD in 1,4-dioxane and at 418 nm for TPD neat films. For the photo-physical characterization, the optical constants of neat films are determined by reflection and transmission measurement, the absorption cross-sections are extracted, and fluorescence spectroscopic parameters are determined. The fluorescence quantum yield of TPD in 1,4-dioxane is 0.69 and for neat TPD films, the fluorescence quantum yield is 0.31.