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 (acs.org)
Image created by minjeong Kim / Nanosphere
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.
The Journal of Physical Chemistry C | Vol 126, No 6 (acs.org)
Image created by minjeong Kim / Nanosphere