Orientation-Dependent Host–Dopant Interactions for Manipulating Charge Transport in Conjugated Polymers

Fengjiao Zhang, Erfan Mohammadi, Ge Qu, Xiaojuan Dai, Ying Diao

Research output: Contribution to journalArticlepeer-review

Abstract

Molecular orientation plays a critical role in controlling carrier transport in organic semiconductors (OSCs). However, this aspect has not been explored for surface doping of OSC thin films. The challenge lies in lack of methods to precisely modulate relative molecular orientation between the dopant and the OSC host. Here, the impact of molecular orientation on dopant–host electronic interactions by large modulation of conjugated polymer orientation via solution coating is reported. Combining synchrotron-radiation X-ray measurements with spectroscopic and electrical characterizations, a quantitative correlation between doping-enhanced charge carrier mobility and the Herman's orientation parameter is presented. This direct correlation can be attributed to enhanced charge-transfer interactions at host/dopant interface with increasing face-on orientation of the polymer. These results demonstrate that the surface doping effect can be fundamentally manipulated by controlling the molecular orientation of the OSC layer, enabling optimization of carrier transport.

Original languageEnglish (US)
Article number2002823
JournalAdvanced Materials
Volume32
Issue number39
DOIs
StatePublished - Oct 1 2020

Keywords

  • carrier mobility optimization
  • chemical doping
  • meniscus-guided coating
  • molecular orientation
  • surface interactions

ASJC Scopus subject areas

  • General Materials Science
  • Mechanics of Materials
  • Mechanical Engineering

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