title: Alkenyl Carboxylic Acid: Engineering the Nanomorphology in Polymer-Polymer Solar Cells as Solvent Additive.
abstract: We have investigated a series of commercially available alkenyl carboxylic acids with different alkenyl chain lengths (trans-2-hexenoic acid (CA-6), trans-2-decenoic acid (CA-10), 9-tetradecenoic acid (CA-14)) for use as solvent additives in polymer-polymer non-fullerene solar cells. We systematically investigated their effect on the film absorption, morphology, carrier generation, transport, and recombination in all-polymer solar cells. We revealed that these additives have a significant impact on the aggregation of polymer acceptor, leading to improved phase segregation in the blend film. This in-depth understanding of the additives effect on the nanomorphology in all-polymer solar cell can help further boost the device performance. By using CA-10 with the optimal alkenyl chain length, we achieved fine phase separation, balanced charge transport, and suppressed recombination in all-polymer solar cells. As a result, an optimal power conversion efficiency (PCE) of 5.71% was demonstrated which is over 50% higher than that of the as-cast device (PCE = 3.71%) and slightly higher than that of devices with DIO treatment (PCE = 5.68%). Compared with widely used DIO, these halogen-free alkenyl carboxylic acids have a more sustainable processing as well as better performance, which may make them more promising candidates for use as processing additives in organic non-fullerene solar cells.
authors.affiliation: Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University , Suzhou, Jiangsu, P. R. China.
authors.forename: Yannan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University , Suzhou, Jiangsu, P. R. China.
authors.forename: Jianyu
authors.identifier: http://orcid.org/0000-0002-5131-1285
authors.initials: J
authors.lastname: Yuan
authors.affiliation: Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University , Suzhou, Jiangsu, P. R. China.
authors.forename: Jianxia
authors.initials: J
authors.lastname: Sun
authors.affiliation: Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University , Suzhou, Jiangsu, P. R. China.
authors.forename: Guanqun
authors.initials: G
authors.lastname: Ding
authors.affiliation: Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University , Suzhou, Jiangsu, P. R. China.
authors.forename: Lu
authors.initials: L
authors.lastname: Han
authors.affiliation: Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University , Suzhou, Jiangsu, P. R. China.
authors.forename: Xufeng
authors.initials: X
authors.lastname: Ling
authors.affiliation: Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University , Suzhou, Jiangsu, P. R. China.
authors.forename: Wanli
authors.initials: W
authors.lastname: Ma
keywords: aggregation; alkenyl carboxylic acid; all-polymer solar cells; blend morphology; processing additives