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Solution-Processed Organic Solar Cells with Power Conversion Efficiencies of 2.5% using Benzothiadiazole/Imide-Based Acceptors
Chemistry of Materials (2011)
  • Laxman Pandey, Georgia Institute of Technology
  • Jason T. Bloking, Stanford University
  • Xu Han, Stanford University
  • Andrew T. Higgs, Stanford University
  • John P. Kastrop, Stanford University
Abstract
A new series of electron-deficient molecules based on a central benzothiadiazole moiety flanked with vinylimides has been synthesized via Heck chemistry and used in solution-processed organic photovoltaics (OPV). Two new compounds, 4,7-bis(4-(N-hexyl-phthalimide)vinyl)benzo[c]1,2,5-thiadiazole (PI-BT) and 4,7-bis(4-(N-hexyl-naphthalimide)vinyl)benzo[c]1,2,5-thiadiazole (NI-BT), show significantly different behaviors in bulk heterojunction (BHJ) solar cells using poly(3-hexylthiophene) (P3HT) as the electron donor. Two-dimensional grazing incidence X-ray scattering (2D GIXS) experiments demonstrate that PI-BT shows significant crystallization in spin-coated thin films, whereas NI-BT does not. Density functional theory (DFT) calculations predict that while PI-BT maintains a planar structure in the ground state, steric interactions cause a twist in the NI-BT molecule, likely preventing significant crystallization. In BHJ solar cells with P3HT as donor, PI-BT devices achieved a large open-circuit voltage of 0.96 V and a maximum device power-conversion efficiency of 2.54%, whereas NI-BT containing devices only achieved 0.1% power-conversion efficiency.
Keywords
  • Organic electronics,
  • Solar cells,
  • Photovoltaic devices,
  • Electron acceptors,
  • N-type materials
Disciplines
Publication Date
2011
Citation Information
Laxman Pandey, Jason T. Bloking, Xu Han, Andrew T. Higgs, et al.. "Solution-Processed Organic Solar Cells with Power Conversion Efficiencies of 2.5% using Benzothiadiazole/Imide-Based Acceptors" Chemistry of Materials Vol. 23 Iss. 24 (2011)
Available at: http://works.bepress.com/laxman_pandey/6/