Next Article in Journal
UV Spectrometric Indirect Analysis of Brominated MWCNTs with UV Active Thiols and an Alkene—Reaction Kinetics, Quantification and Differentiation of Adsorbed Bromine and Oxygen
Previous Article in Journal
Charged Polymers Transport under Applied Electric Fields in Periodic Channels
Materials 2013, 6(7), 3022-3034; doi:10.3390/ma6073022
Article

The Influence of Alkoxy Substitutions on the Properties of Diketopyrrolopyrrole-Phenyl Copolymers for Solar Cells

1,§
,
1,§
,
2
,
3
,
1
,
1
,
1
,
3
,
2
 and
1,*
Received: 20 May 2013 / Revised: 2 July 2013 / Accepted: 9 July 2013 / Published: 22 July 2013
(This article belongs to the Section Materials for Energy Applications)
Download PDF [873 KB, uploaded 22 July 2013]

Abstract

A previously reported diketopyrrolopyrrole (DPP)-phenyl copolymer is modified by adding methoxy or octyloxy side chains on the phenyl spacer. The influence of these alkoxy substitutions on the physical, opto-electronic properties, and photovoltaic performance were investigated. It was found that the altered physical properties correlated with an increase in chain flexibility. Well-defined oligomers were synthesized to verify the observed structure-property relationship. Surprisingly, methoxy substitution on the benzene spacer resulted in higher melting and crystallization temperatures in the synthesized oligomers. This trend is not observed in the polymers, where the improved interactions are most likely counteracted by the larger conformational possibilities in the polymer chain upon alkoxy substitution. The best photovoltaic performance was obtained for the parent polymer: fullerene blends whereas the modifications on the other two polymers result in reduced open-circuit voltage and varying current densities under similar processing conditions. The current densities could be related to different polymer: fullerene blend morphologies. These results show that supposed small structural alterations such as methoxy substitution already significantly altered the physical properties of the parent polymer and also that oligomers and polymers respond divergent to structural alterations made on a parent structure.
Keywords: organic solar cells; conjugated polymers; DPP; synthesis; Density Functional Theory (DFT) organic solar cells; conjugated polymers; DPP; synthesis; Density Functional Theory (DFT)
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Supplement

Share & Cite This Article

Further Mendeley | CiteULike
Export to BibTeX |
EndNote
MDPI and ACS Style

George, Z.; Kroon, R.; Gehlhaar, R.; Gbabode, G.; Lundin, A.; Hellström, S.; Müller, C.; Geerts, Y.; Heremans, P.; Andersson, M.R. The Influence of Alkoxy Substitutions on the Properties of Diketopyrrolopyrrole-Phenyl Copolymers for Solar Cells. Materials 2013, 6, 3022-3034.

View more citation formats

Article Metrics

Comments

Citing Articles

[Return to top]
Materials EISSN 1996-1944 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert