Why holes and electrons separate so well in polymer/fullerene photovoltaic cells

David P. McMahon, David Cheung, Alessandro Troisi

Research output: Contribution to journalArticle

152 Citations (Scopus)

Abstract

The electronic and geometric structure of a prototypical polymer/fullerene interface used in photovoltaic cells (P3HT/PCBM) is investigated theoretically using a combination of classical and quantum simulation methods. It is shown that the electronic structure of P3HT in contact with PCBM is significantly altered compared to bulk P3HT. Due to the additional free volume of the interface, P3HT chains close to PCBM are more disordered, and consequently, they are characterized by an increased band gap. Excitons and holes are therefore repelled by the interface. This provides a possible explanation of the low recombination efficiency and supports the direct formation of “quasi-free” charge-separated species at the interface.
LanguageEnglish
Pages2737–2741
Number of pages5
JournalJournal of Physical Chemistry Letters
Volume2
Issue number21
DOIs
Publication statusPublished - 12 Oct 2011

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Fullerenes
Photovoltaic cells
Free volume
Electronic structure
Polymers
Energy gap
Electrons
Excitons
LDS 751

Keywords

  • organic solar cells
  • electron transfer
  • molecular dynamics
  • disorder

Cite this

McMahon, David P. ; Cheung, David ; Troisi, Alessandro. / Why holes and electrons separate so well in polymer/fullerene photovoltaic cells. In: Journal of Physical Chemistry Letters. 2011 ; Vol. 2, No. 21. pp. 2737–2741.
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Why holes and electrons separate so well in polymer/fullerene photovoltaic cells. / McMahon, David P. ; Cheung, David; Troisi, Alessandro.

In: Journal of Physical Chemistry Letters, Vol. 2, No. 21, 12.10.2011, p. 2737–2741.

Research output: Contribution to journalArticle

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