International Journal of Photoenergy (Jan 2015)

Effect of the Side Chains and Anode Material on Thermal Stability and Performance of Bulk-Heterojunction Solar Cells Using DPP(TBFu)2 Derivatives as Donor Materials

  • Alexander Kovalenko,
  • Jana Honová,
  • Martin Vala,
  • Stanislav Luňák,
  • Ladislav Fekete,
  • Petra Horáková,
  • Lenka Dokládalová,
  • Lubomír Kubáč,
  • Martin Weiter

DOI
https://doi.org/10.1155/2015/734917
Journal volume & issue
Vol. 2015

Abstract

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An optimized fabrication of bulk-heterojunction solar cells (BHJ SCs) based on previously reported diketopyrrolopyrrole donor, ethyl-hexylated DPP(TBFu)2, as well as two new DPP(TBFu)2 derivatives with ethyl-hexyl acetate and diethyl acetal solubilizing side-chains and PC60BM as an acceptor is demonstrated. Slow gradual annealing of the solar cell causing the effective donor-acceptor reorganization, and as a result higher power conversion efficiency (PCE), is described. By replacing a hole transporting layer PEDOT:PSS with MoO3 we obtained higher PCE values as well as higher thermal stability of the anode contact interface. DPP(TBFu)2 derivative containing ethyl-hexyl acetate solubilizing side-chains possessed the best as-cast self-assembly and high crystallinity. However, the presence of ethyl-hexyl acetate and diethyl acetal electrophilic side-chains stabilizes HOMO energy of isolated DPP(TBFu)2 donors with respect to the ethyl-hexylated one, according to cyclic voltammetry.