Issue 3, 2013

Novel polythiophene derivatives functionalized with conjugated side-chain pendants comprising triphenylamine/carbazole moieties for photovoltaic cell applications

Abstract

We synthesized a series of polythiophenes (PTs) featuring 2-ethylhexyl-substituted terthiophene (T) or quaterthiophene (BT) as the conjugated unit in the polymer backbone with pendant conjugated tert-butyl-substituted triphenylamine (tTPA)- or carbazole (tCz)-containing moieties as side chains, namely PTtTPA, PBTtTPA, PTtCz and PBTtCz. Incorporating T and BT moieties into the polymer backbone and attaching tTPA or tCz units promoted efficient conjugation within the extended conjugated frameworks of the polymers, resulting in lower band-gap energies and red-shifting of the maximal UV-Vis absorption wavelength. The higher electron-donating ability of tTPA resulted in broader absorption bands and lower band-gap energies of PTtTPA and PBTtTPA as compared with PTtCz and PBTtCz. Incorporation of the T and BT moieties into the polymer backbone enhanced the compatibility of PT and the fullerene derivative by reducing the side-chain density of PT, thus providing sufficient free volume for efficient incorporation of [6,6]phenyl-C61-butyric acid methyl ester (PC61BM) into the polymer chains. Polymer solar cells (PSCs) were fabricated by spin-coating a blend of each PT with the fullerene derivative (PC61BM) as a composite film-type photoactive layer; PBTtTPA/PC61BM-based PSCs showed superior photovoltaic (PV) performance to PTtTPA/PC61BM-based PSCs in terms of conjugation and absorption band broadness. However, PBTtCz/PC61BM-based PSCs showed inferior PV performance to PTtCz/PC61BM-based PSCs. The lower HOMO level led to a higher open-circuit voltage (Voc; 0.74 V) and larger photo-energy conversion efficiency (η; 2.77%) of PTtCz/PC61BM-based PSCs.

Graphical abstract: Novel polythiophene derivatives functionalized with conjugated side-chain pendants comprising triphenylamine/carbazole moieties for photovoltaic cell applications

Supplementary files

Article information

Article type
Paper
Submitted
02 Jul 2012
Accepted
07 Sep 2012
First published
07 Sep 2012

Polym. Chem., 2013,4, 506-519

Novel polythiophene derivatives functionalized with conjugated side-chain pendants comprising triphenylamine/carbazole moieties for photovoltaic cell applications

H. Wang, J. Tzeng, C. Chou, C. Huang, R. Lee and R. Jeng, Polym. Chem., 2013, 4, 506 DOI: 10.1039/C2PY20477K

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements