Blue light emitting polyphenylene dendrimers with bipolar charge transport moieties

Abstract

Two light-emitting polyphenylene dendrimers with both hole and electron transportin moieties were synthesized and characterized. Both molecules exhibited pure blue emissio solely from the pyrene core and efficient surface-To-core energy transfers when characterized i a nonpolar environment. In particular, the carbazole-And oxadiazole-functionalized dendrime (D1) manifested a pure blue emission from the pyrene core without showing intramolecular charg transfer (ICT) in environments with increasing polarity. On the other hand, the triphenylamine-An oxadiazole-functionalized one (D2) displayed notable ICT with dual emission from both the core an an ICT state in highly polar solvents. D1, in a three-layer organic light emitting diode (OLED) b solution processing gave a pure blue emission with Commission Internationale de l'Éclairage 193 CIE xy = (0.16, 0.12), a peak current efficiency of 0.21 cd/A and a peak luminance of 2700 cd/m2 This represents the first reported pure blue dendrimer emitter with bipolar charge transport an surface-To-core energy transfer in OLEDs.