Does the Electron-Donating Polymer Design Criteria Hold True for the Non-Fullerene Bulk Heterojunction Electron Acceptor Boron Subphthalocyanine? Yes

The performance of boron subphthalocyanine (BsubPc) and phenyl-C₆₁-butyric acid methyl ester (PC₆₁BM) as electron-accepting materials in bulk heterojunction organic photovoltaics (OPVs) with a range of reported literature polymers were simultaneously screened to observe if the design criteria for polymeric electron-donating materials, originally designed for pairing with fullerene derivatives, can be applied to non-fullerene electron acceptors. Initially, the morphology and film formation of the BsubPc-containing active layer films was improved by using a volatile additive, 1,2-dimethoxybenzene, which is known to solubilize a BsubPc but not a representative high-performing polymer (PBTZT-stat-BDTT-8). Thereafter, with the resulting semioptimal fabrication parameters, 10 polymeric electron-donating materials were screened with the BsubPc derivative, PhO-Cl₆BsubPc (phenoxy-hexachloro-boron-subphthalocyanine), and PC₆₁BM. Device metrics demonstrate that the BsubPc-based devices perform in-line with their analogues utilizing PC₆₁BM but can be limited by polymers that have overlapping absorbance with PhO-Cl₆BsubPc, low solubility, or large energy level offsets. Overall, the design aspects of electron-donating polymeric materials that were considered for more than a decade can be applied to non-fullerene or, specifically, BsubPc-based electron acceptors.