Abstract
We applied both bithiazole (BTz)-based homopolymer (PBTz) and BTz-based donor-acceptor polymers (PEDOTBTz) synthesized by direct C-H arylation reaction as donor materials for bulk heterojunction (BHJ) organic photovoltaics (OPVs), and investigated the resulting OPV performances. We found that BHJ layers with BTz-based polymers and fullerene derivatives (PCBMs) spin-coated from a chloroform (CF) solution had a tendency to form large phase separation owing to the strong repulsion of crystalline BTz-based polymers with PCBMs. The resultant power-conversion efficiencies (PCEs) of PEDOTBTz-based BHJ OPVs were approximately 0.6%. After optimizing the spin-coating solvent from CF to a mixture of CF and o-dichlorobenzene, and then changing the interlayer between the ITO and the BHJ layer from PEDOT:PSS to WO3, a PCE of 1.41% was obtained for the PEDOTBTz-based BHJ OPVs.
