Reliability of Small Molecule Organic Photovoltaics with Electron-Filtering Compound Buffer Layers

Quinn Burlingame, Byeongseop Song, Laura Ciammaruchi, Gloria Zanotti, Jeanne Hankett, Zhan Chen, Eugene A. Katz, Stephen R. Forrest

Research output: Contribution to journalArticlepeer-review

24 Scopus citations

Abstract

Electron-filtering compound buffer layers (EF-CBLs) improve charge extraction in organic photovoltaic cells (OPVs) by blending an electron-conducting fullerene with a wide energy gap exciton-blocking molecule. It is found that devices with EF-CBLs with high glass transition temperatures and a low crystallization rate produce highly stable morphologies and devices. The most stable OPVs employ 1:1 2,2′,2″-(1,3,5-benzenetriyl tris-[1-phenyl-1H-benzimidazole] TPBi:C70 buffers that lose <20% of their initial power conversion efficiency of 6.6 ± 0.6% after 2700 h under continuous simulated AM1.5G illumination, and show no significant degradation after 100 days of outdoor aging. When exposed to 100-sun (100 kW m−2) concentrated solar illumination for 5 h, their power conversion efficiencies decrease by <8%. Moreover, it is found that the reliability of the devices employing stable EF-CBLs has either reduced or no dependence on operating temperature up to 130 °C compared with BPhen:C60 devices whose fill factors show thermally activated degradation. The robustness of TPBi:C70 devices under extreme aging conditions including outdoor exposure, high temperature, and concentrated illumination is promising for the future of OPV as a stable solar cell technology.

Original languageEnglish
Article number1601094
JournalAdvanced Energy Materials
Volume6
Issue number21
DOIs
StatePublished - 9 Nov 2016

Keywords

  • degradation
  • solar cells
  • thermal activation

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Materials Science (all)

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