title: Comparative study on pyrido[3,4-b]pyrazine-based sensitizers by tuning bulky donors for dye-sensitized solar cells.
abstract: Dye-sensitized solar cells (DSSCs) with cobalt electrolytes have gained increasing attention. In this Research Article, two new pyrido[3,4-b]pyrazine-based sensitizers with different cores of bulky donors (indoline for DT-1 and triphenylamine for DT-2) were designed and synthesized for a comparative study of their photophysical and electrochemical properties and device performance and were also analyzed through density functional theory calculations. The results of density function theory calculations reveal the limited electronic communication between the biphenyl branch at the cis-position of N-phenylindoline and the indoline core, which could act as an insulating blocking group and inhibit the dye aggregation and charge recombination at the interface of TiO2/dye/electrolyte. As expected, DSSCs based on DT-1 with cobalt redox electrolyte gained a higher photoelectric conversion efficiency of 8.57% under standard AM 1.5 G simulated sunlight, with Jsc = 16.08 mA cm(-2), Voc = 802 mV, and FF = 0.66. Both electrochemical impedance spectroscopy (EIS) and intensity-modulated photovoltage spectroscopy (IMVS) suggest that charge recombination in DSSCs based on DT-1 is much less than that in their counterparts of DT-2, owing to the bigger donor size and the insulating blocking branch in the donor of DT-1.
authors.affiliation: Key Laboratory for Advanced Materials and Institute of Fine Chemicals, East China University of Science and Technology , Shanghai 200237, People's Republic of China.
authors.forename: Xiaoyu
authors.initials: X
authors.lastname: Zhang
authors.forename: Jiangyi
authors.initials: J
authors.lastname: Mao
authors.forename: Dan
authors.initials: D
authors.lastname: Wang
authors.forename: Xin
authors.initials: X
authors.lastname: Li
authors.forename: Jiabao
authors.initials: J
authors.lastname: Yang
authors.forename: Zhongjin
authors.initials: Z
authors.lastname: Shen
authors.forename: Wenjun
authors.initials: W
authors.lastname: Wu
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.forename: Hans
authors.initials: H
authors.lastname: Ågren
authors.forename: Jianli
authors.initials: J
authors.lastname: Hua
keywords: dye-sensitized solar cells; indoline; pyrido[3,4-b]pyrazine; sensitizers; triphenylamine