Polymer Bulletin

, Volume 73, Issue 9, pp 2567–2581 | Cite as

New bulky side chain substituted benzodithiophene based 2D-conjugated polymers for optoelectronic applications

  • Kakaraparthi Kranthiraja
  • Sang Ho Park
  • Woosum Cho
  • Won-Tae Park
  • Yong-Young Noh
  • Sung-Ho JinEmail author
  • Jae Wook LeeEmail author
Original Paper


In order to explore the effect of bulky side chain substituted benzodithiophene (BDT) based polymers on optoelectronic properties, here we have designed and synthesized two new 2D conjugated donor–acceptor (D–A) copolymers P1 and P2 via Stille coupling of 2,3-bis(4-(2-ethylhexyloxy)phenyl)thiophene (BAPT) substituted BDT as (D) unit and 1,3-di(2-bromothien-5-yl)-5-(2-ethylhexyl)thieno[3,4-c]pyrrole-4,6-dione (TPD) or 2,5-ethylhexyl-3,6-bis(5-bromothiophen-2-yl)pyrrolo[3,4-c]-pyrrole-1,4-dione (DPP) as (A) units. The new polymers P1 and P2 showed broad absorption windows with vibronic shoulders indicate ππ stacking of polymer backbones. In addition P1 and P2 showed deep highest occupied molecular orbital (HOMO) energy levels of −5.50, −5.35 eV, respectively which allow delivering high open-circuit voltages (V oc) in bulk heterojunction polymer solar cells (BHJ PSCs). The donor photon energy loss (E g–eV oc) of P1 and P2 are 0.87 and 0.57 which is comparable to the previous reports. BHJ PSCs were fabricated with P1 and P2, and they displayed high V oc of 0.99 and 0.78 V, respectively, with maximum power conversion efficiency of 2.05 and 0.96 % in additive free BHJ PSCs. The polymer field effect transistor mobilities of P1 and P2 are 8.0 × 10−3, 9.2 × 10−5 cm2/V s, respectively.


Bulky side chains Polymer solar cells Open-circuit voltage Conjugated polymers 



This work was supported by grant fund from the National Research Foundation (NRF) (2011-0028320) and the Pioneer Research Center Program through the NRF (2013M3C1A3065522) by the Ministry of Science, ICT and Future Planning (MSIP) of Korea.


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Copyright information

© Springer-Verlag Berlin Heidelberg 2016

Authors and Affiliations

  • Kakaraparthi Kranthiraja
    • 1
  • Sang Ho Park
    • 1
  • Woosum Cho
    • 1
  • Won-Tae Park
    • 2
  • Yong-Young Noh
    • 2
  • Sung-Ho Jin
    • 1
    Email author
  • Jae Wook Lee
    • 3
    Email author
  1. 1.Department of Chemistry Education, Graduate Department of Chemical Materials, Institute for Plastic Information and Energy MaterialsPusan National UniversityBusanRepublic of Korea
  2. 2.Department of Energy and Materials EngineeringDongguk UniversitySeoulSouth Korea
  3. 3.Department of ChemistryDong-A UniversityBusanKorea

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