Impact of fluorine substituted π-bridges on the photovoltaic performance of organic small-molecule donor materials. Issue 9 (9th July 2021)

• Record Type: Journal Article
• Authors: Fan, Dongdong; Fan, Chenling; Fan, Hongyu; Bao, Sunan; Zheng, Yan; Yang, Hang; Zhu, Xianming; Cui, Chaohua; Li, Yongfang
• Is Part Of: Molecular Systems Design and Engineering. Volume 6:Issue 9(2021)
• Page Start: 739
• Page End: 747
• Publication Date: 2021-07-09
• Subjects: Chemistry -- Molecular aspects -- Periodicals; Chemical engineering -- Molecular aspects -- Periodicals; Nanotechnology -- Periodicals; 620.5
• DOI: 10.1039/d1me00045d
• Languages: English
• ISSNs: 2058-9689

Abstract

Abstract : Two analogue small molecules, BDTP-2F with a difluorobenzene π-bridge and BDTP-4F with a tetrafluorobenzene π-bridge, are designed to investigate the impact of a fluorine substituted π-bridge on photovoltaic performance. Abstract : Two analogue molecules, BDTP-2F with difluorobenzene π-bridges and BDTP-4F with tetrafluorobenzene π-bridges, are designed to investigate the impact of fluorine substituted π-bridges on photovoltaic performance. In comparison with BDTP-4F, BDTP-2F has a slightly red-shifted absorption spectrum but has a higher HOMO level, indicating that the increment of fluorine substitutions on the phenyl π-bridge blue-shifts the absorption spectrum and down-shifts the HOMO level of small molecules. Particularly, much different photovoltaic performance is obtained when applying Y6 as an acceptor to blend with BDTP-2F and BDTP-4F as donors, respectively. The device based on BDTP-2F:Y6 yields a power-conversion efficiency (PCE) of 10.21%, while a much lower PCE of 5.76% is achieved for the BDTP-4F:Y6-based device, ascribing to the different morphological properties of the blend films. The results demonstrate that the engineering of fluorine substitutions on the π-bridge is an effective strategy to manipulate the photovoltaic properties of small-molecule donor materials.