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

David P.  McMahon; David Cheung; Alessandro Troisi

doi:10.1021/jz201325g

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

David P. McMahon, David Cheung, Alessandro Troisi

Pure And Applied Chemistry

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172 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.

Original language	English
Pages (from-to)	2737–2741
Number of pages	5
Journal	Journal of Physical Chemistry Letters
Volume	2
Issue number	21
DOIs	https://doi.org/10.1021/jz201325g
Publication status	Published - 12 Oct 2011

Keywords

organic solar cells
electron transfer
molecular dynamics
disorder

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10.1021/jz201325g

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title = "Why holes and electrons separate so well in polymer/fullerene photovoltaic cells",

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.",

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AU - McMahon, David P.

AU - Cheung, David

AU - Troisi, Alessandro

PY - 2011/10/12

Y1 - 2011/10/12

N2 - 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.

AB - 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.

KW - organic solar cells

KW - electron transfer

KW - molecular dynamics

KW - disorder

U2 - 10.1021/jz201325g

DO - 10.1021/jz201325g

M3 - Article

SN - 1948-7185

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JO - Journal of Physical Chemistry Letters

JF - Journal of Physical Chemistry Letters

IS - 21

ER -

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

Abstract

Keywords

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