Effect of Side Substituents Incorporated into π‐Bridges of Quinoxaline‐Based Sensitizers for Dye‐Sensitized Solar Cells. Issue 5 (18th March 2020)

• Record Type: Journal Article
• Authors: Zhang, Wen; Yang, Xichuan; An, Jincheng; Zhang, Li; Cai, Bin; Yang, Kaiyuan
• Is Part Of: Energy technology. Volume 8:Issue 5(2020:May)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-03-18
• Subjects: additional acceptors -- dye-loading amounts -- dye-sensitized solar cells -- intermolecular aggregations -- quinoxaline; Energy development -- Periodicals; Power resources -- Periodicals; 333.79
• DOI: 10.1002/ente.202000032
• Languages: English
• ISSNs: 2194-4288

Abstract

Abstract : Two new metal‐free donor (D)–acceptor (A)–π–A‐type sensitizers with 2, 3‐dihexylquinoxaline (HQ ) and 2, 3‐diphenylquinoxaline (PQ ) moieties as additional acceptors, respectively, coded as ZW002 and ZW003, are synthesized and applied in dye‐sensitized solar cells (DSSCs). Both dyes have broad absorption and large molar absorption coefficients. The sensitizer with the HQ core effectively restrains intermolecular aggregation due to steric hindrance of numerous alkyl chains. A thienyl unit with or without a hexyl branch is used as a π‐bridge. Incorporation of only thienyl groups as a π‐bridge into the sensitizer increases the dye‐loading amount on the TiO2 film due to the smaller molecular size. Using the ZW002 dye with the Co (II/III) redox couple results in DSSCs that exhibit a high photovoltaic conversion efficiency of 8.23% and short‐circuit current density ( J sc ) of 12.43 mA cm −2, an open‐circuit voltage ( V oc ) of 960 mV, and a fill factor (FF) of 0.69. Although ZW003 shows a wider absorption range than that of ZW002, the two additional phenyl groups on the quinoxaline unit contribute to poorer performance (power conversion efficiency [PCE] of 7.43%) due to more serious dye aggregation. Abstract : 2, 3‐Dihexylquinoxaline and 2, 3‐diphenylquinoxaline are incorporated as the auxiliary acceptor to construct ZW sensitizers. Although the absorption spectra are narrower, the device performance of ZW002 is better than ZW003 due to higher dye loading and antiaggregation.