Significant improvement of optoelectronic and photovoltaic properties by incorporating thiophene in a solution-processable D–A–D modular chromophore

Raynor, Aaron M., Gupta, Akhil, Plummer, Christopher M., Jackson, Sam L., Bilic, Ante, Patil, Hemlata, Sonar, Prashant, & Bhosale, Sheshanath V. (2015) Significant improvement of optoelectronic and photovoltaic properties by incorporating thiophene in a solution-processable D–A–D modular chromophore. Molecules, 20(12), pp. 21787-21801.

View at publisher (open access)


Through the incorporation of a thiophene functionality, a novel solution-processable small organic chromophore was designed, synthesized and characterized for application in bulk-heterojunction solar cells. The new chromophore, (2Z,2′Z)-2,2′-(1,4-phenylene)bis(3-(5-(4-(diphenylamino)phenyl)thiophen-2-yl)acrylonitrile) (coded as AS2), was based on a donor–acceptor–donor (D–A–D) module where a simple triphenylamine unit served as an electron donor, 1,4-phenylenediacetonitrile as an electron acceptor, and a thiophene ring as the π-bridge embedded between the donor and acceptor functionalities. AS2 was isolated as brick-red, needle-shaped crystals, and was fully characterized by 1H- and 13C-NMR, IR, mass spectrometry and single crystal X-ray diffraction. The optoelectronic and photovoltaic properties of AS2 were compared with those of a structural analogue, (2Z,2′Z)-2,2′-(1,4-phenylene)bis(3-(4-(diphenylamino)phenyl)-acrylonitrile) (AS1). Benefiting from the covalent thiophene bridges, compared to AS1 thin solid film, the AS2 film showed: (1) an enhancement of light-harvesting ability by 20%; (2) an increase in wavelength of the longest wavelength absorption maximum (497 nm vs. 470 nm) and (3) a narrower optical band-gap (1.93 eV vs. 2.17 eV). Studies on the photovoltaic properties revealed that the best AS2-[6,6]-phenyl-C61-butyric acid methyl ester (PC61BM)-based device showed an impressive enhanced power conversion efficiency of 4.10%, an approx. 3-fold increase with respect to the efficiency of the best AS1-based device (1.23%). These results clearly indicated that embodiment of thiophene functionality extended the molecular conjugation, thus enhancing the light-harvesting ability and short-circuit current density, while further improving the bulk-heterojunction device performance. To our knowledge, AS2 is the first example in the literature where a thiophene unit has been used in conjunction with a 1,4-phenylenediacetonitrile accepting functionality to extend the π-conjugation in a given D–A–D motif for bulk-heterojunction solar cell applications.

Impact and interest:

2 citations in Scopus
2 citations in Web of Science®
Search Google Scholar™

Citation counts are sourced monthly from Scopus and Web of Science® citation databases.

These databases contain citations from different subsets of available publications and different time periods and thus the citation count from each is usually different. Some works are not in either database and no count is displayed. Scopus includes citations from articles published in 1996 onwards, and Web of Science® generally from 1980 onwards.

Citations counts from the Google Scholar™ indexing service can be viewed at the linked Google Scholar™ search.

ID Code: 99797
Item Type: Journal Article
Refereed: Yes
Keywords: solution-processable; bulk-heterojunction devices; donor–acceptor–donor; triphenylamine; thiophene; 1,4-phenylenediacetonitrile
DOI: 10.3390/molecules201219798
ISSN: 1420-3049
Divisions: Current > Schools > School of Chemistry, Physics & Mechanical Engineering
Current > QUT Faculties and Divisions > Science & Engineering Faculty
Copyright Owner: Copyright 2015 by the authors; licensee MDPI, Basel, Switzerland
Copyright Statement: This article is an open access article distributed under the terms and conditions of the Creative Commons by Attribution
(CC-BY) license (
Deposited On: 11 Oct 2016 22:23
Last Modified: 14 Oct 2016 04:50

Export: EndNote | Dublin Core | BibTeX

Repository Staff Only: item control page