Synthesis of pyrene-cored dendrimers with 9-phenylcarbazole-based dendrons and their thermal, photophysical and electrochemical properties

Three generations of dendrimers (G1, G2 and G3) with a pyrene core and 9-phenylcarbazole derivatives dendrons have been designed and synthesized by convergent approach. Their chemical structures were well characterized by means of 1H NMR, IR spectroscopy, MALDI-TOF MS and elemental analysis. The studies revealed interesting effects of topological variation with incremental generation number on the thermal, photophysical and electrochemical properties of the dendrimers. The results showed that they displayed excellent thermal stability with 5% weight-loss temperature up to 610 °C and high glass-transition temperature (260 °C for G3). The HOMO and energy band gaps of materials could be modulated by changing the generation of the dendrimers. Compared to G1 and G2, the higher generation G3 had significantly enhanced photoluminescent quantum yield from 86.9 to 99.5%, and exhibited good stability for hole and electron injection.