Molecular engineering strategy for high efficiency fullerene-free organic solar cells using conjugated 1,8-naphthalimide and fluorenone building blocks

Do, Thu Trang and Pham, Hong Duc and Manzhos, Sergei and Bell, John M and Sonar, Prashant (2017) Molecular engineering strategy for high efficiency fullerene-free organic solar cells using conjugated 1,8-naphthalimide and fluorenone building blocks. ACS Applied Materials and Interfaces, 9 (20). pp. 16967-16976. ISSN 1944-8244


Abstract

We designed, synthesized, and characterized a series of novel electron deficient small molecule nonfullerene acceptors based on 1,8-naphthalimide (NAI) and 9-fluorenone (FN) with different branched alkyl chains using various techniques. These molecules are based on an acceptor-donor-acceptor-donor-acceptor (A1-D-A2-D-A1) molecular design configuration with NAI as the end-capping acceptor (A1), FN as electron-withdrawing central (A2) group, and thiophene ring as a donor (D) unit. These materials are named as NAI-FN-NAI (BO) and NAI-FN-NAI (HD) where BO and HD represent butyloctyl and hexyldecyl alkyl groups, respectively. To further modify energy levels of these materials, we converted the weak electron withdrawing ketonic group (C=O) attached to the FN moiety of NAI-FN-NAI (BO) to a stronger electron withdrawing cyano group (C≡N) to obtain the compound NAI-FCN-NAI (BO) by keeping the same alkyl chain. The optical, electrochemical, and thermal properties of the new acceptors were studied. The materials exhibited higher to medium band gaps, low lowest unoccupied molecular orbital (LUMO) energy levels, and highly thermally stable properties. Organic solar cell devices employing conventional poly(3-hexylthiophene) (P3HT) a donor polymer and the newly designed small molecules as the acceptor were investigated. Among all new materials, organic solar cell devices based on NAI-FN-NAI (BO) as an acceptor exhibit the highest performance with an open circuit voltage (VOC) of 0.88 V, a short-circuit current density (JSC) of 9.1 mAcm-2, a fill factor (FF) of 45%, and an overall power conversion efficiency (PCE) of 3.6%. This is the first report of 9-fluorenone based nonfullerene acceptor with P3HT donor in organic solar cell devices with such a promising performance.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Files associated with this item cannot be displayed due to copyright restrictions.
Faculty/School / Institute/Centre: Current - Research and Innovation Division (12 Jul 2012 -)
Faculty/School / Institute/Centre: Current - Research and Innovation Division (12 Jul 2012 -)
Date Deposited: 10 Sep 2020 23:53
Last Modified: 11 Sep 2020 02:31
Uncontrolled Keywords: 1.8-naphthalimide; 9-fluorenone; nonfullerene; electron acceptors; organic solar cells
Fields of Research (2008): 09 Engineering > 0912 Materials Engineering > 091299 Materials Engineering not elsewhere classified
Fields of Research (2020): 40 ENGINEERING > 4016 Materials engineering > 401699 Materials engineering not elsewhere classified
Identification Number or DOI: https://doi.org/10.1021/acsami.6b16395
URI: http://eprints.usq.edu.au/id/eprint/39360

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