One-Step Synthesis of Precursor Oligomers for Organic Photovoltaics: A Comparative Study between Polymers and Small Molecules
Journal article, 2015

Two series of oligomers TQ and rhodanine end-capped TQ-DR were synthesized using a facile one-step method. Their optical, electrical, and thermal properties and photovoltaic performances were systematically investigated and compared. The TQ series of oligomers were found to be amorphous, whereas the TQ-DR series are semicrystalline. For the TQ oligomers, the results obtained in solar cells show that as the chain length of the oligomers increases, an increase in power conversion efficiency (PCE) is obtained. However, when introducing 3-ethylrhodanine into the TQ oligomers as end groups, the PCE of the TQ-DR series of oligomers decreases as the chain length increases. Moreover, the TQ-DR series of oligomers give much higher performances compared to the original amorphous TQ series of oligomers owing to the improved extinction coefficient (epsilon) and crystallinity afforded by the rhodanine. In particular, the highly crystalline oligomer TQ5-DR, which has the shortest conjugation length shows a high hole mobility of 0.034 cm(2) V-1 s(-1) and a high PCE of 3.14%, which is the highest efficiency out of all of the six oligomers. The structure-property correlations for all of the oligomers and the TQ1 polymer demonstrate that structural control of enhanced intermolecular interactions and crystallinity is a key for small molecules/oligomers to achieve high mobilities, which is an essential requirement for use in OPVs.

amorphous

oligomers

organic photovoltaics

crystallinity

hole mobility

one-step method

Author

W. Li

South China University of Technology

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry, Polymer Technology

D. J. Wang

Linköping University

S. H. Wang

Linköping University

W. Ma

Xi'an Jiaotong University

Svante Hedström

Lund University

David James

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry, Polymer Technology

Xiaofeng Xu

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry, Polymer Technology

P. Persson

Lund University

S. Fabiano

Linköping University

M. Berggren

Linköping University

Olle Inganäs

Linköping University

F. Huang

South China University of Technology

Ergang Wang

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry, Polymer Technology

ACS Applied Materials & Interfaces

1944-8244 (ISSN) 1944-8252 (eISSN)

Vol. 7 49 27106-27114

Subject Categories

Materials Engineering

DOI

10.1021/acsami.5b09460

More information

Latest update

11/22/2018