Enhancing Dye‐Sensitized Solar Cell Performances by Molecular Engineering: Highly Efficient π‐Extended Organic Sensitizers. Issue 9 (23rd July 2014)

• Record Type: Journal Article
• Authors: Grisorio, Roberto; De Marco, Luisa; Agosta, Rita; Iacobellis, Rosabianca; Giannuzzi, Roberto; Manca, Michele; Mastrorilli, Piero; Gigli, Giuseppe; Suranna, Gian Paolo
• Is Part Of: ChemSusChem. Volume 7:Issue 9(2014:Sep.)
• Page Start: 2659
• Page End: 2669
• Publication Date: 2014-07-23
• Subjects: Green chemistry -- Periodicals; Sustainable engineering -- Periodicals; Chemistry -- Periodicals; Chemical engineering -- Periodicals; 660
• DOI: 10.1002/cssc.201402164
• Languages: English
• ISSNs: 1864-5631

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>This study deals with the synthesis and characterization of two π‐extended organic sensitizers (<bold>G1</bold> and <bold>G2</bold>) for applications in dye‐sensitized solar cells. The materials are designed with a D–A–π–A structure constituted by i) a triarylamine group as the donor part, ii) a dithienyl‐benzothiadiazole chromophore followed by iii) a further ethynylene‐thiophene (<bold>G1</bold>) or ethynylene‐benzene (<bold>G2</bold>) π‐spacer and iv) a cyano‐acrylic moiety as acceptor and anchoring part. An unusual structural extension of the π‐bridge characterizes these structures. The so‐configured sensitizers exhibit a broad absorption profile, the origin of which is supported by density functional theory. The absence of hypsochromic shifts as a consequence of deprotonation as well as notable optical and electrochemical stabilities are also observed. Concerning the performances in devices, electrochemical impedance spectroscopy indicates that the structural modification of the π‐spacer mainly increases the electron lifetime of <bold>G2</bold> with respect to <bold>G1</bold>. In devices, this feature translates into a superior power conversion efficiency of <bold>G2</bold>, reaching 8.1 %. These results are comparable to those recorded for <bold>N719</bold> and are higher with respect to literature congeners, supporting further structural engineering of the π‐bridge extension in the search for better performing π‐extended organic sensitizers.</p> </abstract>