Synthesis and Charge-Transporting Properties of Dibenzothiphene Dioxide-Based Polysiloxanes.

We designed and synthesized a dibenzothiphene dioxide-based homopolysiloxane, PDBTSi, and a carbazole-dibenzothiophene dioxide alternating copolysiloxane, PCzSi-alt-PDBTSi, respectively. Both PDBTSi and PCzSi-alt-PDBTSi possess an improved solubility, good film-forming ability and extremely high thermal stability due to introduction of polysiloxane main chains. Meanwhile, PDBTSi and PCzSi-alt-PDBTSi exhibit high triplet energy levels of 2.95 eV and 3.05 eV, respectively. Furthermore, PDBTSi possesses good electron-transporting property with an electron mobility of 1.02×10-4  cm2  V-1  s-1 and a relatively balanced hole mobility of 8.76×10-5  cm2  V-1  s-1 . In contrast, PCzSi-alt-PDBTSi exhibits an electron mobility of 4.65×10-5  cm2  V-1  s-1 and a hole mobility of 1.17×10-4  cm2  V-1  s-1 . Therefore, our results here provide a feasible strategy to obtain solution-processed polysiloxane materials with high and balanced electron- and hole-transporting properties.