Get 20M+ Full-Text Papers For Less Than $1.50/day. Start a 14-Day Trial for You or Your Team.

Learn More →

Molecular Understanding of the Open‐Circuit Voltage of Polymer:Fullerene Solar Cells

Molecular Understanding of the Open‐Circuit Voltage of Polymer:Fullerene Solar Cells The origin of open‐circuit voltage (VOC) was studied for polymer solar cells based on a blend of poly(3‐hexylthiophene) (P3HT) and seven fullerene derivatives with different LUMO energy levels and side chains. The temperature dependence of J–V characteristics was analyzed by an equivalent circuit model. As a result, VOC increased with the decrease in the saturation current density J0 of the device. Furthermore, J0 was dependent on the activation energy EA for J0, which is related to the HOMO–LUMO energy gap between P3HT and fullerene. Interestingly, the pre‐exponential term J00 for J0 was larger for pristine fullerenes than for substituted fullerene derivatives, suggesting that the electronic coupling between molecules also has substantial impact on VOC. This is probably because the recombination is non‐diffusion‐lmilited reaction depending on electron transfer at the P3HT/fullerene interface. In summary, the origin of VOC is ascribed not only to the relative HOMO–LUMO energy gap but also to the electronic couplings between fullerene/fullerene and polymer/fullerene. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Advanced Energy Materials Wiley

Molecular Understanding of the Open‐Circuit Voltage of Polymer:Fullerene Solar Cells

Loading next page...
 
/lp/wiley/molecular-understanding-of-the-open-circuit-voltage-of-polymer-XVpMAgEvoh

References (64)

Publisher
Wiley
Copyright
Copyright © 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim
ISSN
1614-6832
eISSN
1614-6840
DOI
10.1002/aenm.201100549
Publisher site
See Article on Publisher Site

Abstract

The origin of open‐circuit voltage (VOC) was studied for polymer solar cells based on a blend of poly(3‐hexylthiophene) (P3HT) and seven fullerene derivatives with different LUMO energy levels and side chains. The temperature dependence of J–V characteristics was analyzed by an equivalent circuit model. As a result, VOC increased with the decrease in the saturation current density J0 of the device. Furthermore, J0 was dependent on the activation energy EA for J0, which is related to the HOMO–LUMO energy gap between P3HT and fullerene. Interestingly, the pre‐exponential term J00 for J0 was larger for pristine fullerenes than for substituted fullerene derivatives, suggesting that the electronic coupling between molecules also has substantial impact on VOC. This is probably because the recombination is non‐diffusion‐lmilited reaction depending on electron transfer at the P3HT/fullerene interface. In summary, the origin of VOC is ascribed not only to the relative HOMO–LUMO energy gap but also to the electronic couplings between fullerene/fullerene and polymer/fullerene.

Journal

Advanced Energy MaterialsWiley

Published: Feb 1, 2012

There are no references for this article.