Synthesis and characterization of wide range light absorbing poly(dithieno[3,2-b:2′,3′-d]thiophene-alt-3,6-bis(thiophen-2-yl)-2, 5-di-n-octyl-pyrrolo[3,4-c]pyrrole-1,4-dione) for polymer solar cells

Chun Young Lee, Bongsoo Kim, Kyung Hwan Kim, Youngwoon Yoon, Min Woo Lee, Dong Hoon Choi, Min Jae Ko, Honggon Kim, Doh Kwon Lee, Kyungkon Kim

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

We designed and synthesized a new low band gap donor-acceptor copolymer (PDTDPP-Oct) composed of alternating dithieno[3,2-b:2′,3′-d] thiophene and bis-thienyl-diketopyrrolo[3,4-c]pyrrole units. The polymer films showed a very broad absorption band that extended up to 950 nm. Thermogravimetric analysis revealed good thermal stability and a high glass transition temperature of 128 °C. The highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of the polymer were estimated to be -5.01 and -3.70 eV, respectively. Bulk heterojunction polymer solar cells were fabricated with the structure: ITO/PEDOT:PSS/polymer:PCBM/Al. The introduction of 1,8-octanedithiol as a processing additive to the polymer/PCBM blend solution significantly improved the device performance relative to devices prepared from the blend solution without the additive. This cell gave a short circuit current of -1.8 mA/cm2, an open circuit voltage of 0.60 V, and a fill factor of 0.52, yielding a power conversion efficiency of 0.55%. The performance improvements were mainly attributed to the fine morphology of the blend film.

Original languageEnglish
Pages (from-to)64-68
Number of pages5
JournalSynthetic Metals
Volume164
Issue number1
DOIs
Publication statusPublished - 2013 Jan 31

Keywords

  • Low band gap polymer
  • Morphology
  • Polymer solar cells
  • Power conversion efficiency
  • Wide range light absorption

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry

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