High-Efficiency P3HT-Based All-Polymer Solar Cells with a Thermodynamically Miscible Polymer Acceptor

Poly(3-hexylthiophene) (P3HT) is the most classical conjugated polymer for organic photovoltaics due to its low-cost and synthetic scalability. However, P3HT-based organic photovoltaics suffer from inferior device performance with respect to donor-acceptor copolymers. Particularly, the device performance of P3HT-based all-polymer solar cells (all-PSCs) is rather poor due to the challenges in reaching ideal bulk-heterojunction morphology. Herein, highly efficient P3HT-based all-PSCs by blending P3HT with a thermodynamic miscible polymer acceptor are reported. Among the three state-of-the-art polymer acceptors (N2200, PYT, and DCNBT-IDT), N2200 and PYT are thermodynamically immiscible with P3HT and thus led to excessive phase separation when blended with P3HT, whereas DCNBT-IDT displayed proper thermodynamic miscibility with P3HT and generated the formation of well-mixed fibrillary active layer morphology. As a result, a power conversion efficiency of 7.35% has been achieved by P3HT:DCNBT-IDT blend, which is a new record for P3HT-based all-PSCs and largely higher than any previous results. Broad implication for further efficiency enhancement of P3HT-based all-PSCs is provided in the results and a promising pathway to realize highly efficient yet cost-effective solar energy production is suggested.

Automated summary

This study reports highly efficient all-polymer solar cells based on P3HT by blending it with a thermodynamically miscible polymer acceptor. The well-mixed fibrillary active layer morphology generated by the blend leads to a record power conversion efficiency of 7.35% for P3HT-based all-PSCs.