Organic Photovoltaics Based on Solution Cast Polymers and Boron Subphthalocyanines – Hybrid Device Architectures Enabling Novel Material Combinations

Solution-cast films of crystalline electron donating poly(3,3”’-didodecylquaterthiophene) (PQT-12) were studied in pseudo-planar heterojunction (PPHJ) organic photovoltaic devices (OPVs) paired with boron subphthalocyanine (BsubPc) as the electron acceptor layer, and the effects of crystallinity domain size and layer thickness were investigated. Annealed, 10-20 nm films of intermediate-sized crystals were 40% more efficient than un-annealed PQT-12 layers and had comparable efficiency to their fullerene-based BHJ counterparts, demonstrating the ability of polymer|BsubPc PPHJ OPVs to accommodate highly crystalline polymers with a tendency to phase segregate and create devices with favorable electrical properties. These polymer|BsubPc PPHJs were further studied with the new amorphous copolymer electron donating material PBTZT-stat-BDTT-8. While optimized PPHJ devices of PBTZT-stat-BDTT-8|BsubPc had substantially lower efficiency than PBTZT-stat-BDTT-8|fullerene BHJs (which were free of morphological problems), they demonstrated comparable performance to their BHJ equivalents due to ideal morphology, presenting a pathway forward for OPV design of otherwise phase segregating polymer|BsubPc pairings.M.A.S