Structural variations to a donor polymer with low energy losses

Jianyu Yuan, Niva A. Ran, Michael J. Ford, Ming Wang, Mahesh Kumar Ravva, Cheng Kang Mai, Xiaofeng Liu, Jean Luc Brédas, Thuc Quyen Nguyen, Wanli Ma, Guillermo C. Bazan

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

Two regioregular narrow bandgap conjugated polymers with a D′-A-D-A repeat unit architecture, namely PIFCF and PSFCF, were designed and synthesized. Both polymers contain strictly organized fluorobenzo[c][1,2,5]thiadiazole (FBT) orientations and different solubilizing side chains for solution processing. Compared to the previously reported asymmetric pyridyl-[2,1,3]thiadiazole (PT) based regioregular polymer, namely PIPCP, PIFCF and PSFCF exhibit wider bandgaps, tighter π-π stacking, and improved hole mobilities. When incorporated into solar cells with fullerene acceptors, the Eloss = Eg - eVoc values of PIFCF and PSFCF devices are increased compared to solar cells based on PIPCP. Determination of Ect in these solar cells reveals that, relative to PIPCP, PIFCF solar cells lose more energy from Eg - Ect, and PSFCF solar cells lose more energy from both Eg - Ect and Ect - eVoc. The close structural relationship between PIPCP and PIFCF provides an excellent framework to establish molecular features that impact the relationship between Eg and Ect. Theoretical calculations predict that Eloss of PIFCF:PC61BM would be higher than in the case of PIPCP:PC61BM, due to greater Eg - Ect. These findings provide insight into the design of high performance, low voltage loss photovoltaic polymeric materials with desirable optoelectronic properties.

Original languageEnglish (US)
Pages (from-to)18618-18626
Number of pages9
JournalJournal of Materials Chemistry A
Volume5
Issue number35
DOIs
StatePublished - 2017
Externally publishedYes

ASJC Scopus subject areas

  • Chemistry(all)
  • Renewable Energy, Sustainability and the Environment
  • Materials Science(all)

Fingerprint

Dive into the research topics of 'Structural variations to a donor polymer with low energy losses'. Together they form a unique fingerprint.

Cite this