Polymer small molecule acceptors could be the key to practical polymer solar cells

Solar power is an essential element in the clean energy future required to combat climate change. But demand for flexible, low-cost, and efficient solar cells reaches beyond traditional grid power with applications in portable electronics, wearable technology, and transportation.

Polymer solar cells could potentially offer many of these benefits but suffer from low efficiency and stability compared to conventional solar cells. Recent advancements in polymer small molecule acceptors (PSMAs) could bring them up to speed. Khelifi and Luscombe review these technological achievements and reflect on areas of growth in the field.

“What sets PSMAs apart is their unique characteristics and potential benefits,” said author Wissem Khelifi. “Unlike traditional non-polymer based small molecule acceptors, PSMAs, specifically all-polymer solar cells, take a novel approach by utilizing an n-type conjugated polymer as the electron acceptor and a p-type conjugated polymer as the electron donor. This design choice offers distinct advantages such as exceptional morphological stability, remarkable mechanical flexibility, excellent stretchability, and outstanding mechanical durability.”

The researchers highlight the benefits of PSMAs, with improved stability, efficiency, and strong absorbance in the near-infrared region, and compare two promising types of PSMAs.

Still, they make recommendations to improve intramolecular charge transfer and absorption redshift and suggest methods to enhance stability. In addition to power demands, the researchers identify practical considerations for PSMA designs, such as reducing cost, designing building blocks, and commercial scalability.

“Our review demonstrates the potential of PSMAs for advancing polymer solar cells,” said Khelifi. “We are committed to addressing synthesis challenges, enhancing efficiency, and improving stability for practical applications.”

Source: “Advances in polymerized small-molecule acceptors for improved performance in all-polymer solar cells,” by Wissem Khelifi and Christine Luscombe, Chemical Physics Reviews (2023). The article can be accessed at https://doi.org/10.1063/5.0169728 .