Organic solar cells based on three-dimensionally percolated polythiophene nanowires with enhanced charge transport

Joo Hyun Kim, Min Kim, Hiroshi Jinnai, Tae Joo Shin, Haena Kim, Jong Hwan Park, Sae Byeok Jo, Kilwon Cho

Research output: Contribution to journalArticle

33 Citations (Scopus)

Abstract

The influence of micrometer-scale poly(3-hexylthiophene) (P3HT) nanowires (NWs) and P3HT nanocrystals (NCs) on the photocurrent generation in photoactive layers having various thickness values was investigated. Self-organizing P3HT NWs were fabricated using a marginal solvent. Transmission electron microtomography was used to characterize the vertical and horizontal crystalline morphologies of the NWs and their intergrain percolation networks in the active layers. The interpenetrating P3HT NWs promoted charge transport, as demonstrated by the enhanced percolation probability and the reduction in bimolecular recombination. The photovoltaic performances were enhanced as the photoactive layer thickness increased because internal quantum efficiencies of the solar devices prepared with active layers having NWs were maintained with varying thicknesses, suggesting that the conversion of absorbed photons into a photocurrent proceeded efficiently. By contrast, the photovoltaic performances of an NC-only photoactive layer were reduced by the increase in thickness due to its poorly developed percolation pathways. The incorporation of P3HT NWs into the P3HT:indene-C60 bisadduct photoactive layers yielded a device power conversion efficiency (PCE) of 5.42%, and the photocurrent did not decrease significantly up to a thickness of 600 nm, resulting in a PCE of 3.75%, 70% of the maximum PCE of 5.42%.

Original languageEnglish
Pages (from-to)5640-5650
Number of pages11
JournalACS Applied Materials and Interfaces
Volume6
Issue number8
DOIs
Publication statusPublished - 2014 Apr 23
Externally publishedYes

Keywords

  • charge transport
  • percolation pathway
  • percolation probability
  • photoactive layer thickness
  • polythiophene nanowire
  • transmission electron microtomography

ASJC Scopus subject areas

  • Materials Science(all)

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