Thermoset Matrices for Thermally Stable Organic Solar Cells through Green Solvent Process

Abstract

Organic solar cells (OSCs) have gained considerable attention from the scientific community in recent decades due to their remarkable power conversion efficiency (PCE), flexibility, and cost-effectiveness in producing large-area batteries. Despite the ongoing research efforts that have led to a PCE exceeding 19% for single-junction OSCs and surpassing 20% for multi-junction OSCs, the commercialization of these devices is hampered by their poor stability, reliance on specific additives, and the use of toxic solvents. To address these shortcomings, this study focuses on investigating the 3 * 3 thermosets matrix to facilitate the selection of precursors for in-situ crosslinking thermosets. Furthermore, in this study, we fabricated the devices using green solvents to narrow the gap between PCE and stability under environmentally friendly conditions. We utilized PTQ10: BTP-BO4Cl as the model system and employed tetrahydrofuran (THF) as an eco-friendly solvent. The research focused on examining the thermoset's glass transition temperature (Tg), modulus and morphology properties. The resulting cross-linked thermoset network has high-density hydrogen bonding and network grids, which helps to stabilize the morphology of the active layer. The findings indicated that selecting a thermoset with high Tg, high modulus (4-8 MPa), and good uniformity as an in-situ crosslinking additive would be beneficial. These results can guide the selection of universal in-situ crosslinking thermosets and aid in improving the stability of various organic electronic devices.