Abstract
We present here a series of wide-band-gap (E g : >1.8 eV) polymer donors by incorporating thiophene-flanked phenylene as an electron-donating unit and quinoxaline as an electron-Accepting co-unit to attain large open-circuit voltages (V oc s) and short-circuit currents (J sc s) in nonfullerene organic solar cells (OSCs). Fluorination was utilized to fine-Tailor the energetics of polymer frontier molecular orbitals (FMOs) by replacing a variable number of H atoms on the phenylene moiety with F. It was found that fluorination can effectively modulate the polymer backbone planarity through intramolecular noncovalent S···F and/or H···F interactions. Polymers (P2-P4) show an improved molecular packing with a favorable face-on orientation compared to their nonfluorinated analogue (P1), which is critical to charge carrier transport and collection. When mixed with IDIC, a nonfullerene acceptor, P3 with two F atoms, achieves a remarkable V oc of 1.00 V and a large J sc of 15.99 mA/cm 2 , simultaneously, yielding a power-conversion efficiency (PCE) of 9.7%. Notably, the 1.00 V V oc is among the largest values in the IDIC-based OSCs, leading to a small energy loss (E loss : 0.62 eV) while maintaining a large PCE. The P3:IDIC blend shows an efficient exciton dissociation through hole transfer even under a small energy offset of 0.16 eV. Further fluorination leads to the polymer P4 with increased chain-Twisting and mismatched FMO levels with IDIC, showing the lowest PCE of 2.93%. The results demonstrate that quinoxaline-based copolymers are promising donors for efficient OSCs and the fluorination needs to be fine-Adjusted to optimize the interchain packing and physicochemical properties of polymers. Additionally, the structure-property correlations from this work provide useful insights for developing wide-band-gap polymers with low-lying highest occupied molecular orbitals to minimize E loss and maximize V oc in nonfullerene OSCs for efficient power conversion.
| Original language | English |
|---|---|
| Pages (from-to) | 23235-23246 |
| Number of pages | 12 |
| Journal | ACS Applied Materials and Interfaces |
| Volume | 10 |
| Issue number | 27 |
| DOIs | |
| Publication status | Published - 2018 Jul 11 |
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Keywords
- energy losses
- fluorination
- nonfullerene organic solar cells
- open-circuit voltages
- polymer semiconductors
ASJC Scopus subject areas
- Materials Science(all)
Cite this
Quinoxaline-Based Wide Band Gap Polymers for Efficient Nonfullerene Organic Solar Cells with Large Open-Circuit Voltages. / Yang, Jie; Uddin, Mohammad Afsar; Tang, Yumin; Wang, Yulun; Wang, Yang; Su, Huimin; Gao, Rutian; Chen, Zhi Kuan; Dai, Junfeng; Woo, Han Young; Guo, Xugang.
In: ACS Applied Materials and Interfaces, Vol. 10, No. 27, 11.07.2018, p. 23235-23246.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Quinoxaline-Based Wide Band Gap Polymers for Efficient Nonfullerene Organic Solar Cells with Large Open-Circuit Voltages
AU - Yang, Jie
AU - Uddin, Mohammad Afsar
AU - Tang, Yumin
AU - Wang, Yulun
AU - Wang, Yang
AU - Su, Huimin
AU - Gao, Rutian
AU - Chen, Zhi Kuan
AU - Dai, Junfeng
AU - Woo, Han Young
AU - Guo, Xugang
PY - 2018/7/11
Y1 - 2018/7/11
N2 - We present here a series of wide-band-gap (E g : >1.8 eV) polymer donors by incorporating thiophene-flanked phenylene as an electron-donating unit and quinoxaline as an electron-Accepting co-unit to attain large open-circuit voltages (V oc s) and short-circuit currents (J sc s) in nonfullerene organic solar cells (OSCs). Fluorination was utilized to fine-Tailor the energetics of polymer frontier molecular orbitals (FMOs) by replacing a variable number of H atoms on the phenylene moiety with F. It was found that fluorination can effectively modulate the polymer backbone planarity through intramolecular noncovalent S···F and/or H···F interactions. Polymers (P2-P4) show an improved molecular packing with a favorable face-on orientation compared to their nonfluorinated analogue (P1), which is critical to charge carrier transport and collection. When mixed with IDIC, a nonfullerene acceptor, P3 with two F atoms, achieves a remarkable V oc of 1.00 V and a large J sc of 15.99 mA/cm 2 , simultaneously, yielding a power-conversion efficiency (PCE) of 9.7%. Notably, the 1.00 V V oc is among the largest values in the IDIC-based OSCs, leading to a small energy loss (E loss : 0.62 eV) while maintaining a large PCE. The P3:IDIC blend shows an efficient exciton dissociation through hole transfer even under a small energy offset of 0.16 eV. Further fluorination leads to the polymer P4 with increased chain-Twisting and mismatched FMO levels with IDIC, showing the lowest PCE of 2.93%. The results demonstrate that quinoxaline-based copolymers are promising donors for efficient OSCs and the fluorination needs to be fine-Adjusted to optimize the interchain packing and physicochemical properties of polymers. Additionally, the structure-property correlations from this work provide useful insights for developing wide-band-gap polymers with low-lying highest occupied molecular orbitals to minimize E loss and maximize V oc in nonfullerene OSCs for efficient power conversion.
AB - We present here a series of wide-band-gap (E g : >1.8 eV) polymer donors by incorporating thiophene-flanked phenylene as an electron-donating unit and quinoxaline as an electron-Accepting co-unit to attain large open-circuit voltages (V oc s) and short-circuit currents (J sc s) in nonfullerene organic solar cells (OSCs). Fluorination was utilized to fine-Tailor the energetics of polymer frontier molecular orbitals (FMOs) by replacing a variable number of H atoms on the phenylene moiety with F. It was found that fluorination can effectively modulate the polymer backbone planarity through intramolecular noncovalent S···F and/or H···F interactions. Polymers (P2-P4) show an improved molecular packing with a favorable face-on orientation compared to their nonfluorinated analogue (P1), which is critical to charge carrier transport and collection. When mixed with IDIC, a nonfullerene acceptor, P3 with two F atoms, achieves a remarkable V oc of 1.00 V and a large J sc of 15.99 mA/cm 2 , simultaneously, yielding a power-conversion efficiency (PCE) of 9.7%. Notably, the 1.00 V V oc is among the largest values in the IDIC-based OSCs, leading to a small energy loss (E loss : 0.62 eV) while maintaining a large PCE. The P3:IDIC blend shows an efficient exciton dissociation through hole transfer even under a small energy offset of 0.16 eV. Further fluorination leads to the polymer P4 with increased chain-Twisting and mismatched FMO levels with IDIC, showing the lowest PCE of 2.93%. The results demonstrate that quinoxaline-based copolymers are promising donors for efficient OSCs and the fluorination needs to be fine-Adjusted to optimize the interchain packing and physicochemical properties of polymers. Additionally, the structure-property correlations from this work provide useful insights for developing wide-band-gap polymers with low-lying highest occupied molecular orbitals to minimize E loss and maximize V oc in nonfullerene OSCs for efficient power conversion.
KW - energy losses
KW - fluorination
KW - nonfullerene organic solar cells
KW - open-circuit voltages
KW - polymer semiconductors
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U2 - 10.1021/acsami.8b04432
DO - 10.1021/acsami.8b04432
M3 - Article
VL - 10
SP - 23235
EP - 23246
JO - ACS applied materials & interfaces
JF - ACS applied materials & interfaces
SN - 1944-8244
IS - 27
ER -