Oligo(phenyl-ethynylene)s for electroluminescence and distributed feedback laser action

Abstract We investigated the electroluminescence (EL) and optically pumped laser emission characteristics of oligo(phenyl-ethynylene)s end-capped with naphtyl groups and bearing dodecyloxy side-chains. Oligomers (oNPE x ) made of 3- or 5-aryl groups are dispersed in poly(vinylcarbazole) (PVK) as a hole-transporting matrix to study EL properties. The emission spectrum of the trimer oNPE3 is centered at 460 nm, slightly blue shifted with respect to the pure phenyl derivative. The typical diode structure is composed of an indium tin oxide (ITO) anode ITO/oNPE x /PVK/and aluminium cathode. The EL spectrum matches photoluminescence (PL). Emission color changes with the concentration from violet to blue for oNPE3 and blue to blue-green for oNPE5 and oNPE5 b . Thin film of oNPE x /PVK also show laser emission around 447 nm in a distributed feedback laser (DFBL) optical pumping scheme. PVK acts in this case as an amorphous laser host matrix and oNPE x shows laser emission tunable by varying the incidence angle of the pump beam onto the film.