Systematic investigation of absorption, fluorescence and laser properties of some p- and m-oligophenylenes

Absorption, fluorescence and laser properties of ten selected aromatic compounds from the oligophenylene family are studied experimentally at room temperature (293 K). The first eight compounds are arranged in such a way that odd numbered compounds reveal 1Lb→1A fluorescence, while even numbered compounds show 1La→1A fluorescence. The quantum yield of fluorescence, γ, and the decay time, τf, of non-deaerated and deaerated cyclohexane solutions are measured. All p-polyphenyles exhibit excellent laser action, while m-polyphenyles do not produce laser oscillation under any conditions. The values of KST and other fluorescence parameters measured are used for various practical purposes and theoretical considerations.