title: Molecular Engineering of Pyrido[3,4-b]pyrazine-Based Donor-Acceptor-π-Acceptor Organic Sensitizers: Effect of Auxiliary Acceptor in Cobalt- and Iodine-Based Electrolytes.
abstract: Due to the ease of tuning its redox potential, the cobalt-based redox couple has been extensively applied for highly efficient dye-sensitized solar cells (DSSCs) with extraordinarily high photovoltages. However, a cobalt electrolyte needs particular structural changes in the organic dye components to obtain such high photovoltages. To achieve high device performance, specific requirements in the molecular tailoring of organic sensitizers still need to be met. Besides the need for large electron donors, studies of the auxiliary acceptor segment of donor-acceptor-π-acceptor (D-A-π-A) organic sensitizers are still rare in molecular optimization in the context of cobalt electrolytes. In this work, two novel organic D-A-π-A-type sensitizers (IQ13 and IQ17) have been developed and exploited in cobalt- and iodine-based redox electrolyte DSSCs, specifically to provide insight into the effect of π-bridge modification in different electrolytes. The investigation has been focused on the additional electron-withdrawing acceptor capability with grafted long alkoxy chains. Optoelectronic transient measurements have indicated that IQ17 containing a pyrido[3,4-b]pyrazine moiety bearing long alkoxyphenyl chains is more suitable for application in cobalt-based DSSCs.
authors.affiliation: Shanghai Key Laboratory of Functional Materials Chemistry, Key Laboratory for Advanced Materials and Institute of Fine Chemicals, East China University of Science & Technology, 130 Meilong Road, Shanghai 200237 (P. R. China).|College of Chemistry and Material Science, Hebei Normal University, No. 20, East Road of Nan ErHuan, Shijiazhuang 050024 (P. R. China).
authors.forename: Bo
authors.initials: B
authors.lastname: Liu
authors.affiliation: Laboratory for Photonics and Interfaces, Institute of Chemical Sciences and Engineering, Swiss Federal Institute of Technology, 1015 Lausanne (Switzerland).
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Giordano
authors.affiliation: Shanghai Key Laboratory of Functional Materials Chemistry, Key Laboratory for Advanced Materials and Institute of Fine Chemicals, East China University of Science & Technology, 130 Meilong Road, Shanghai 200237 (P. R. China).
authors.forename: Kai
authors.initials: K
authors.lastname: Pei
authors.affiliation: Laboratory for Photonics and Interfaces, Institute of Chemical Sciences and Engineering, Swiss Federal Institute of Technology, 1015 Lausanne (Switzerland).
authors.forename: Jean-David
authors.initials: JD
authors.lastname: Decoppet
authors.affiliation: Shanghai Key Laboratory of Functional Materials Chemistry, Key Laboratory for Advanced Materials and Institute of Fine Chemicals, East China University of Science & Technology, 130 Meilong Road, Shanghai 200237 (P. R. China). whzhu@ecust.edu.cn.
authors.forename: Wei-Hong
authors.initials: WH
authors.lastname: Zhu
authors.affiliation: Laboratory for Photonics and Interfaces, Institute of Chemical Sciences and Engineering, Swiss Federal Institute of Technology, 1015 Lausanne (Switzerland). shaik.zakeer@epfl.ch.
authors.forename: Shaik M
authors.initials: SM
authors.lastname: Zakeeruddin
authors.affiliation: Laboratory for Photonics and Interfaces, Institute of Chemical Sciences and Engineering, Swiss Federal Institute of Technology, 1015 Lausanne (Switzerland). michael.graetzel@epfl.ch.
authors.forename: Michael
authors.initials: M
authors.lastname: Grätzel
keywords: auxiliary acceptor; cobalt-based electrolyte; donor-acceptor systems; dyes/pigments; optoelectronic transient measurement; organic sensitizers