Article

Incomplete Exciton Harvesting from Fullerenes in Bulk Heterojunction Solar Cells

Department of Applied Physics, Stanford University, Stanford, California 94305, USA.
Nano Letters (Impact Factor: 13.59). 10/2009; 9(12):4037-41. DOI: 10.1021/nl902205n
Source: PubMed

ABSTRACT

We investigate the internal quantum efficiencies (IQEs) of high efficiency poly-3-hexylthiophene:[6,6]-phenyl-C(61)-butyric acid methyl ester (P3HT:PCBM) solar cells and find them to be lower at wavelengths where the PCBM absorbs. Because the exciton diffusion length in PCBM is too small, excitons generated in PCBM decay before reaching the donor-acceptor interface. This result has implications for most state of the art organic solar cells, since all of the most efficient devices use fullerenes as electron acceptors.

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