title: Organic sensitizers featuring thiophene derivative based donors with improved stability and photovoltaic performance.
abstract: Thiophene derivatives, including thieno[3,2-b][1]benzothiophene (TBT), benzo[b]thiophene (BT), 2-phenylthieno[3,2-b]thiophene (PTT) and 2-phenylthiophene (PT), have been introduced as donors for the construction of triarylamine organic dyes (M52, M53, M56, M57 and M52A). The absorption, electrochemical and photovoltaic properties as well as the stabilities of these dyes are systematically investigated and compared with the reference dye (M55), whose donor is composed of the hexyloxybenzene (HOB) unit. It is found that introducing the TBT, BT, PTT or PT donors positively shifted the HOMO and LUMO levels of the organic dyes, providing a larger driving force for regeneration and reducing the energy loss for electron injection. In addition, we found that M52, which contains the TBT unit, exhibited better photovoltaic performance and photostability as compared to the reference dye. In contrast, M53 displayed the lowest efficiency and stability of these dyes, indicating that the BT unit is not a good building block for donors. Interestingly, upon the incorporation of the mixed donor (TBT-HOB), M52A achieved a desirable driving force for regeneration without a loss in light absorption, thus resulting in a further improved photovoltaic performance with respect to that of M52. This work demonstrates that introducing donors based on thiophene derivatives is a good strategy for tuning the energy levels and thereby enhancing the efficiency of the resulting devices.
authors.affiliation: Tianjin Key Laboratory of Organic Solar Cells and Photochemical Conversion, Department of Applied Chemistry, Tianjin University of Technology, Tianjin 300384, P. R. China. liangmao717@126.com xuesong@ustc.edu.cn.
authors.forename: Kai
authors.initials: K
authors.lastname: Miao
authors.affiliation: Tianjin Key Laboratory of Organic Solar Cells and Photochemical Conversion, Department of Applied Chemistry, Tianjin University of Technology, Tianjin 300384, P. R. China. liangmao717@126.com xuesong@ustc.edu.cn and Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), Collaborative Innovation Center of Chemical Science and Engineering, College of Chemistry, Nankai University, Tianjin 300071, P. R. China.
authors.forename: Mao
authors.identifier: http://orcid.org/0000-0003-0808-3851
authors.initials: M
authors.lastname: Liang
authors.affiliation: Jiangsu Provincial Key Laboratory of Palygorskite Science and Applied Technology, College of Chemical Engineering, Huaiyin Institute of Technology, Jiangsu 223003, P. R. China.
authors.forename: Zhihui
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Tianjin Key Laboratory of Organic Solar Cells and Photochemical Conversion, Department of Applied Chemistry, Tianjin University of Technology, Tianjin 300384, P. R. China. liangmao717@126.com xuesong@ustc.edu.cn.
authors.forename: Chunyao
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Tianjin Key Laboratory of Organic Solar Cells and Photochemical Conversion, Department of Applied Chemistry, Tianjin University of Technology, Tianjin 300384, P. R. China. liangmao717@126.com xuesong@ustc.edu.cn.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Sun
authors.affiliation: Tianjin Key Laboratory of Organic Solar Cells and Photochemical Conversion, Department of Applied Chemistry, Tianjin University of Technology, Tianjin 300384, P. R. China. liangmao717@126.com xuesong@ustc.edu.cn.
authors.forename: Song
authors.initials: S
authors.lastname: Xue