Charge-Transfer States in Organic Solar Cells: Understanding the Impact of Polarization, Delocalization, and Disorder
Type
ArticleKAUST Department
KAUST Solar Center (KSC)Laboratory for Computational and Theoretical Chemistry of Advanced Materials
Material Science and Engineering Program
Physical Science and Engineering (PSE) Division
Date
2017-05-17Online Publication Date
2017-05-17Print Publication Date
2017-05-31Permanent link to this record
http://hdl.handle.net/10754/623702
Metadata
Show full item recordAbstract
We investigate the impact of electronic polarization, charge delocalization, and energetic disorder on the charge-transfer (CT) states formed at a planar C60/pentacene interface. The ability to examine large complexes containing up to seven pentacene molecules and three C60 molecules allows us to take explicitly into account the electronic polarization effects. These complexes are extracted from a bilayer architecture modeled by molecular dynamics simulations and evaluated by means of electronic-structure calculations based on long-range-separated functionals (ωB97XD and BNL) with optimized range-separation parameters. The energies of the lowest charge-transfer states derived for the large complexes are in very good agreement with the experimentally reported values. The average singlet-triplet energy splittings of the lowest CT states are calculated not to exceed 10 meV. The rates of geminate recombination as well as of dissociation of the triplet excitons are also evaluated. In line with experiment, our results indicate that the pentacene triplet excitons generated through singlet fission can dissociate into separated charges on a picosecond time scale, despite the fact that their energy in C60/pentacene heterojunctions is slightly lower than the energies of the lowest CT triplet states.Citation
Zheng Z, Tummala NR, Fu Y-T, Coropceanu V, Brédas J-L (2017) Charge-Transfer States in Organic Solar Cells: Understanding the Impact of Polarization, Delocalization, and Disorder. ACS Applied Materials & Interfaces. Available: http://dx.doi.org/10.1021/acsami.7b02193.Sponsors
We acknowledge the financial support of this work at the Georgia Institute of Technology by the Department of the Navy, Office of Naval Research, under the MURI “Center for Advanced Organic Photovoltaics” (Award Nos. N00014-14-1-0580 and N00014-16-1-2520) and by King Abdullah University of Science and Technology (V.C.). A KAUST competitive research funding and the Office of Naval Research – Global (Award No. N62909-15-1-2003) supported the work at King Abdullah University of Science and Technology.Publisher
American Chemical Society (ACS)PubMed ID
28481497Additional Links
http://pubs.acs.org/doi/full/10.1021/acsami.7b02193ae974a485f413a2113503eed53cd6c53
10.1021/acsami.7b02193
Scopus Count
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