Pyrene-cored dendrimer with carbazole derivatives as dendrons: synthesis, properties and application in white light-emitting diode

A new dendrimer using pyrene as core and carbazole derivative as dendron has been successfully prepared via Suzuki coupling reaction. Its chemical structure was confirmed through 1H NMR, elemental analysis and MALDI-TOF MS methods. The dendrimer synthesized possessed excellent thermal stability with initial decomposition temperature over 470 °C and high fluorescence quantum yield of 86%. The luminescence spectra showed that, relative to the solution sample, the emission peaks of the solid dendrimer film were apparently broadened and red-shifted, indicating the strong π–π stacking effect between the pyrene moieties. By doping 1.5% of the dendrimer in 4,4′-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (NPB), a light-emitting diode device was fabricated in the ITO/NPB/NPB : dendrimer (1.5%)/TPBI/Mg : Ag configuration, which emitted a white color with Commission Internationale de L'Eclairage (CIEx,y) coordinates of (0.29, 0.34) and a maximum brightness of 1300 cd m−2, exhibiting promising potential in white light-emitting diode application.