Low-bandgap poly(4H-cyclopenta[def]phenanthrene) derivatives with 4,7-dithienyl-2,1,3-benzothiadiazole unit for photovoltaic cells

Jinwoo Kim, Sung Heum Park, Shinuk Cho, Youngeup Jin, Jaehong Kim, Il Kim, Jin Sook Lee, Joo Hyun Kim, Han Young Woo, Kwanghee Lee, Hongsuk Suh

Research output: Contribution to journalArticlepeer-review

33 Citations (Scopus)


A series of conjugated polymer bearing 4H-cyclopenta[def]phenanthrene (CPP) unit have been synthesized and was evaluated in bulk heterojunction solar cell. The alternating copolymers with CPP unit were incorporated with 4,7-dithienyl-2,1,3-benzothiadiazole (DTBT) unit by Suzuki conditions. The newly synthesized copolymers, poly(2,6-((4,4-bis(2-ethylhexyl)-4H-cyclopenta[def]phenanthrene))-alt-(4,7-((2-thienyl)-2,1,3-benzothiadiazole))) (PCPP-DTBT), and poly(2,6-(4,4-bis(4-((2-ethylhexyl)oxy)phenyl)-4H-cyclopenta[def]phenanthrene)-alt-(4,7-((2-thienyl)-2,1,3-benzothiadiazole))) (PBEHPCPP-DTBT), contain dialkyl and bis(alkoxyphenyl) groups in the CPP unit, respectively. The HOMO-LUMO energy bandgaps of these materials, estimated from UV-vis spectroscopy and cyclic voltammetry (CV), were 2.00 eV for PCPP-DTBT and 1.80 eV for PBEHPCPP-DTBT. Bulk heterojunction solar cells based on the blends of the polymers with [6,6]phenyl-C71-butyric acid methyl ester (PC71BM) gave power conversion efficiencies as 1.00% for PCPP-DTBT and 1.12% for PBEHPCPP-DTBT under AM 1.5, 100 mW/cm2.

Original languageEnglish
Pages (from-to)390-396
Number of pages7
Issue number2
Publication statusPublished - 2010 Jan 21
Externally publishedYes

Bibliographical note

Funding Information:
This work was supported by the Korea Research Foundation Grant funded by the Korean Government (MOEHRD, Basic Research Promotion Fund) (KRF-2008-314-C00200).


  • Benzothiadiazole
  • Cyclopentaphenanthrene
  • Polymer solar cell

ASJC Scopus subject areas

  • Organic Chemistry
  • Polymers and Plastics
  • Materials Chemistry


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