title: Effect of different numbers of -CH2- units on the performance of isoquinolinium dyes.
abstract: Three new dyes have been synthesized to investigate the influence of the distance between the electron acceptor and TiO2 surface on the performance of dye-sensitized solar cells (DSSCs). In these dyes, the isoquinolinium acceptor, with a -(CH2)nCOOH anchoring group, and a functionalized triphenylamine donor are separated by an oligothiophene bridge. The physical and electrochemical properties of the dyes were investigated systematically. The results prove that different numbers of -CH2- units between the isoquinolinium acceptor and the carboxyl anchoring group have a less pronounced effect on the physical and electrochemical properties of these dyes. However, when applied in DSSCs, a sharp decrease in the short-circuit current (Jsc) was observed with increasing numbers of -CH2- units. For example, the device containing the organic dye bearing three -CH2- units produced the lowest Jsc of 7.94 mA·cm(-2). In contrast, the device containing the dye bearing only one -CH2- unit exhibited the highest Jsc of 13.88 mA·cm(-2). The higher photocurrent obtained with the device incorporating the dye with one -CH2- unit resulted in a higher power conversion efficiency of 6.8%.
authors.affiliation: State Key Laboratory of Fine Chemicals, DUT-KTH Joint Education and Research Centre on Molecular Devices, Dalian University of Technology (DUT) , 2 Linggong Road, 116024 Dalian, China.
authors.forename: Jianghua
authors.initials: J
authors.lastname: Zhao
authors.forename: Xichuan
authors.initials: X
authors.lastname: Yang
authors.forename: Yan
authors.initials: Y
authors.lastname: Hao
authors.forename: Ming
authors.initials: M
authors.lastname: Cheng
authors.forename: Jie
authors.initials: J
authors.lastname: Tian
authors.forename: Licheng
authors.initials: L
authors.lastname: Sun