Article abstract
Nature Photonics 3, 297 - 302 (2009)
Published online: 26 April 2009 | doi:10.1038/nphoton.2009.69
Subject Category: Solar energy and photovoltaic technology
Bulk heterojunction solar cells with internal quantum efficiency approaching 100%
Sung Heum Park1,2, Anshuman Roy1, Serge Beaupré3, Shinuk Cho1,2, Nelson Coates1, Ji Sun Moon1,2, Daniel Moses1, Mario Leclerc3, Kwanghee Lee1,2 & Alan J. Heeger1,2
Abstract
We report the fabrication and measurement of solar cells with 6% power conversion efficiency using the alternating co-polymer, poly[N-9''-hepta-decanyl-2,7-carbazole-alt-5,5-(4',7'-di-2-thienyl-2',1',3'-benzothiadiazole) (PCDTBT) in bulk heterojunction composites with the fullerene derivative [6,6]-phenyl C70-butyric acid methyl ester (PC70BM). The PCDTBT/PC70BM solar cells exhibit the best performance of any bulk heterojunction system studied to date, with JSC = 10.6 mA cm-2, VOC = 0.88 V, FF = 0.66 and 
e = 6.1% under air mass 1.5 global (AM 1.5 G) irradiation of 100 mW cm-2. The internal quantum efficiency is close to 100%, implying that essentially every absorbed photon results in a separated pair of charge carriers and that all photogenerated carriers are collected at the electrodes.
- Center for Polymers and Organic Solids, University of California at Santa Barbara, Santa Barbara, California 93106, USA
- Heeger Center for Advanced Materials, Gwangju Institute of Science and Technology, Gwangju 500-712, South Korea
- Department of Chemistry, University of Laval, G1K 7P4 Quebec City, Quebec, Canada
Correspondence to: Kwanghee Lee1,2 e-mail: klee@gist.ac.kr
Correspondence to: Alan J. Heeger1,2 e-mail: ajhe@physics.ucsb.edu
