Intrachain Delocalization Effect of Charge Carriers on the Charge-Transfer State Dynamics in Organic Solar Cells

Dongki Lee, Jaewon Lee, Dong Hun Sin, Se Gyo Han, Hansol Lee, Wookjin Choi, Hyojung Kim, Jaebum Noh, Jungho Mun, Woong Sung, Sang Woo Kim, Byeong Geun Jeong, Sung Hyuk Kim, Junsuk Rho, Mun Seok Jeong, Kilwon Cho

Research output: Contribution to journalArticlepeer-review


We studied the charge-generation mechanism in low-bandgap polymer (P4TNTz-2F)-fullerene bulk heterojunction (BHJ) organic solar cells (OSCs) using transient absorption (TA) spectroscopy. The highly crystalline nanowire structure of P4TNTz-2F in a blend film prepared with chlorobenzene (CB) and 1,8-diiodooctane (DIO) induced more long-lived charge carriers than those in a blend film prepared with CB only. Pump-wavelength-dependent TA data revealed that the increased charge-delocalization by the intrachain ordering of P4TNTz-2F in the blend film prepared with CB/DIO is the key factor to increasing the OSC efficiency. The intrachain charge-delocalization increased the charge-transfer (CT) state lifetime and suppressed geminate recombination losses, resulting in the efficient dissociation of CT states into free carriers. Our findings provide new insights into the excited-state dynamics study of BHJ blends, which can serve as a good guide for the development of novel OSC materials.

Original languageEnglish
Pages (from-to)3171-3179
Number of pages9
JournalJournal of Physical Chemistry C
Issue number6
Publication statusPublished - 2022 Feb 17

Bibliographical note

Funding Information:
This work was supported by a grant (Code No. 2011-0031628) from the Center for Advanced Soft Electronics under the Global Frontier Research Program of the Korean government Ministry of Science and ICT (MSIT). This work was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2020R1I1A1A01054660) and the Faculty Research Fund of Sejong University in 2021. This work was also supported by the NRF grants funded by the MSIT (NRF-2019R1A2B5B02070657/NRF-2019M3D1A1078299/NRF-2019R1A2C1086262).

Publisher Copyright:
© 2022 American Chemical Society

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Energy(all)
  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films


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