High-performance flexible tandem polymer solar cell employing a novel cross-linked conductive fullerene as an electron transport layer

Chih Yu Chang, Wen Kuan Huang, Yu Chia Chang, Kuan Ting Lee, Hao Yi Siao

Research output: Contribution to journalArticle

26 Citations (Scopus)


A novel thermally cross-linkable, n-doped conductive fullerene material is developed by incorporating tetrabutylammonium iodide (TBAI) as the dopant into an azidofullerene derivative PCBN3. The application of TBAI-doped cross-linked PCBN3 film as the electron transport layer (ETL) in polymer solar cells (PSCs) delivers several remarkable features, including easy solution-processability, reasonable electrical conductivity (2.8 × 10-3 S cm-1), good ambient and chemical stability, fine-tunability of the work function of the electrode, wide applicability in a variety of efficient polymers, relative weak thickness-dependent performance property, and moderate cross-linking temperature (∼140 °C). With this ETL, a single-junction solar cell based on the blend of poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl]] (PTB7) with [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) delivers a power conversion efficiency (PCE) up to 8.8%, which is superior to that of the device with state-of-the-art ETL titanium oxide (TiOx) film. In addition, the application of using this ETL in double-junction tandem structure solar cells is also demonstrated, with a PCE exceeding 10%. More significantly, the low processing temperature of this ETL makes it compatible with the fabrication of flexible tandem solar cells, and an impressively high PCE of 9.2% is demonstrated, which represents the highest PCE ever reported for flexible PSCs.

Original languageEnglish
Pages (from-to)1869-1875
Number of pages7
JournalChemistry of Materials
Issue number5
Publication statusPublished - Mar 10 2015
Externally publishedYes


ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Materials Chemistry

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