High-Efficiency Ternary Organic Solar Cells with a Good Figure-of-Merit Enabled by Two Low-Cost Donor Polymers

Here, we combine two donor polymers with a relatively short synthesis method and fabricate ternary organic solar cells (OSCs) with a high efficiency and a decent figure-of-merit. A series of characterizations show that the optimal morphology of the ternary blend is the result of the coupling and competition of PTQ10 and PTVT-T, where the molecular packing and phase separation motif of PTQ10 is broken but the strong aggregation of PTVT-T is suppressed, resulting in efficient charge transport and collection, as well as suppressed bimolecular recombination. Moreover, a previously reported solvent-vapor-assisted casting method, taken as an understanding-guided optimization, pushes the optimal system's efficiency to 19.11%. Furthermore, PTVT-T-containing systems clearly show better light soaking and thermal stability than the PTQ10 binary control system, benefiting from the durable polymer matrix. Our work provides a useful approach for developing efficient, stable, and low-cost OSCs based on state-of-the-art donor/acceptor systems through morphology control of the ternary design.

Automated summary

In this study, we fabricated ternary organic solar cells with high efficiency and decent performance by combining two donor polymers using a simple synthesis method. Our results indicate that the optimal morphology of the ternary blend is achieved through the coupling and competition between PTQ10 and PTVT-T, leading to efficient charge transport and suppressed bimolecular recombination. Furthermore, the optimized solvent-vapor-assisted casting method improved the efficiency of the optimal system to 19.11%.