Photovoltaic performance of block copolymer devices is independent of the crystalline texture in the active layer

Changhe Guo, Youngmin Lee, Yen Hao Lin, Joseph Strzalka, Cheng Wang, Alexander Hexemer, Cherno Jaye, Daniel A. Fischer, Rafael Verduzco, Qing Wang, Enrique D. Gomez

Research output: Contribution to journalArticlepeer-review

23 Scopus citations

Abstract

The electronic properties of organic semiconductors are strongly influenced by intermolecular packing. When cast as thin films, crystalline π-conjugated molecules are strongly textured, potentially leading to anisotropic charge transport. Consequently, it is hypothesized that the orientation of crystallites in the active layer plays an important role in charge extraction and organic photovoltaic device performance. Here we demonstrate orientation control of molecular packing from mostly face-on to edge-on configurations in the active layer of P3HT-b-PFTBT block copolymer photovoltaics using 1-chloronaphthalene as a solvent additive. The effect of molecular orientations in P3HT crystals on charge transport and solar cell performance is examined. We find that optimized photovoltaic device performance is independent of the crystalline texture of P3HT. Our observations provide further insights into the molecular organization required for efficient charge transport and overall device efficiencies. The dominant crystal orientation, whether face-on or edge-on, is not critical to block copolymer solar cells. Instead, a broad distribution of crystallite orientations ensures pathways for charge transport in any direction and enables efficient charge extraction in photovoltaic devices.

Original languageEnglish (US)
Pages (from-to)4599-4608
Number of pages10
JournalMacromolecules
Volume49
Issue number12
DOIs
StatePublished - Jun 28 2016

All Science Journal Classification (ASJC) codes

  • Organic Chemistry
  • Polymers and Plastics
  • Inorganic Chemistry
  • Materials Chemistry

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