ACS_the journal of physical chemistry c


ACS_the journal of physical chemistry c

February 17, 2022

Volume 126, Issue 6

Pages 2931-3304

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

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.

  • 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

The Journal of Physical Chemistry C | Vol 126, No 6 (

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