Near-infrared squaraine sensitizers bearing benzo[c, d]indolenine as an acceptor moiety. (November 2015)

• Record Type: Journal Article
• Authors: Maeda, Takeshi; Nitta, Shohei; Sano, Yohei; Tanaka, Shota; Yagi, Shigeyuki; Nakazumi, Hiroyuki
• Is Part Of: Dyes and pigments. Volume 122(2015)
• Page Start: 160
• Page End: 167
• Publication Date: 2015-11
• Subjects: Squaraine dye -- Benzo[c, d]indolenine -- Near infrared -- Dye-sensitized solar cell -- Low band gap -- Aggregation; Dyes and dyeing -- Periodicals; Pigments -- Periodicals; 667.2
• DOI: 10.1016/j.dyepig.2015.06.022
• Languages: English
• ISSNs: 0143-7208

Abstract

Abstract: Near-infrared absorbing unsymmetrical squaraine dyes bearing benzo[ c, d ]indolenine as an acceptor moiety have been synthesized and their light-absorbing properties and performance as sensitizers for dye-sensitized solar cells were studied. A molecular-orbital calculation indicated that the electron distribution moved from the cyclobutene skeleton to the benzo[ c, d ]indolenine components with a carboxy group through photoexcitation. The squaraines exhibited prominent absorption properties in the range 600–900 nm, whereas these dyes show a tendency to aggregate in solution as well as on a titania due to an effect of the π-extended benzo[ c, d ]indolenine. Their absorption and electrochemical properties revealed that these dyes have deep lowest unoccupied molecular orbital levels which are close to the potential of the titania conduction band. Dye-sensitized solar cell using the present dyes achieved a spectral response in the range from 940 nm to 400 nm. These results indicated that benzo[ c, d ]indolenine with a carboxy group can be applied to the components for near-infrared-absorbing sensitizers in photovoltaic cells. Graphical abstract: Highlights: A benzo[ c, d ]indolenium salt with a carboxy group was synthesized as an anchor component for DSSCs. Squaraine sensitizers exhibit NIR absorption due to the benzo[ c, d ]indolenine unit. Asymmetrical benzo[c, d]indolenine based squaraines showed aggregation tendencies. Benzo[ c, d ]indolenine-based squaraines contribute to the NIR response of DSSCs.