A New Dithienylbenzotriazole-Based Poly( 2,7-carbazole) for Efficient Photovoltaics

A new dithienyl benzotriazole-based conjugated polymer was synthesized by Suzuki coupling reaction. The polymer was found to be soluble in common organic solvents, such as chloroform, tetrahydrofuran and chlorobenzene, with excellent film-forming properties. The structure of the polymer was confirmed by H-1 NMR, the molecular weights determined by GPC and the thermal properties investigated by TGA and DSC. The polymer films exhibited an absorption band in the wavelength range 300 to 610 nm. Preliminary photovoltaic cells based on the composite structure of indium tin oxide (ITO)/PEDOT:PSS/PCDTBTz:PC60BM (1:2 w/w)/Al showed an open-circuit voltage of 0.92 V, a power conversion efficiency of 2.2% and a short circuit current of 5.33 mA cm(-2).