Molecular-weight-dependent nanoscale morphology in silole-containing cyclopentadithiophene polymer and fullerene derivative blends

Jen Hsien Huang, Fang-Chung Chen, Cheng Lun Chen, Annie Tzuyu Huang, Yu Sheng Hsiao, Chin Min Teng, Feng Wen Yen, Pelin Chen, Chih Wei Chu*

*Corresponding author for this work

Research output: Contribution to journalArticle

21 Scopus citations

Abstract

We have investigated the effect of polymer molecular weight (MW) on the morphology and efficiency of bulk heterojunction (BHJ) solar cells comprised of poly[(4,4′-bis(2-ethylhexyl)dithieno[3,2-b:2′,3′-d]silole)-2, 6-diyl-alt-(5,5′-thienyl-4,4′-dihexyl-2,2′-bithiazole)-2, 6-diyl] (Si-PCPDTTBT) and [6,6]-phenyl C61 butyric acid methyl ester (PCBM). Striking morphological changes are observed in BHJ films upon the change of the polymer MW. Atomic force microscopy and transmission electron microscopy studies suggest that high MW polymer generated high degree of phase separation, leading to formation of an interpenetrating network for carrier transport. The X-ray diffraction investigation indicated that increased π-π stacking in Si-PCPDTTBT with increasing polymer MWs results in an increase in hole mobility of Si-PCPDTTBT and electron mobility of PCBM as well as the red shift absorption spectrum in BHJ films. The solar cells based on PCBM with high-MW Si-PCPDTTBT deliver power conversion efficiencies of 3.33%.

Original languageEnglish
Pages (from-to)1755-1762
Number of pages8
JournalOrganic Electronics
Volume12
Issue number11
DOIs
StatePublished - 1 Jan 2011

Keywords

  • Bulk heterojunction
  • Exciton lifetime
  • Molecular weight
  • Morphology
  • Phase separation
  • Solar cells

Fingerprint Dive into the research topics of 'Molecular-weight-dependent nanoscale morphology in silole-containing cyclopentadithiophene polymer and fullerene derivative blends'. Together they form a unique fingerprint.

  • Cite this