Carbazole-based small molecule electron donors: Syntheses, characterization, and material properties. (March 2018)

• Record Type: Journal Article
• Authors: Sippola, Roosa J.; Hadipour, Afshin; Kastinen, Tuuva; Vivo, Paola; Hukka, Terttu I.; Aernouts, Tom; Heiskanen, Juha P.
• Is Part Of: Dyes and pigments. Volume 150(2018)
• Page Start: 79
• Page End: 88
• Publication Date: 2018-03
• Subjects: Absorption -- Carbazole -- DFT -- Electron donor -- Organic solar cell -- Suzuki-Miyaura -- Synthesis; Dyes and dyeing -- Periodicals; Pigments -- Periodicals; 667.2
• DOI: 10.1016/j.dyepig.2017.11.014
• Languages: English
• ISSNs: 0143-7208

Abstract

Abstract: Efficient synthetic methods for carbazole-based small molecule electron donors with donor–acceptor ( D – A ) and A – D – A type structures were developed. In order to study the relation between chemical structures and material properties, the prepared compounds were characterized in detail using absorption spectroscopy, differential pulse voltammetry, and computational methods. In addition, symmetrical A – D – A type compounds were tested as an active layer component in bulk heterojunction based organic solar cell (OSC) devices with conventional structure. The results show that the two compound types have many similar properties. However, the extended molecular structure of A – D – A type compounds offer better film forming properties and higher molar absorption coefficients compared with the D – A type materials. Furthermore, the attachment of fluoro substituents in the A units has a positive effect on all solar cell device parameters. Moreover, the computational studies revealed that the molecular structures are twisted between the central carbazole D unit and π -bridge which may result in inefficient intramolecular charge transfer and, also, relatively limited short-circuit currents in OSC devices. Graphical abstract: Highlights: Novel D – A and A – D – A type small molecule electron donors were synthesized. Characterization by computational, electrochemical, and spectroscopic methods. A – D – A type materials were tested as active layer components in OSC devices. Relations between molecular structures and properties are studied and discussed.