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Electric Field Faci...
Electric Field Facilitating Hole Transfer in Non-Fullerene Organic Solar Cells with a Negative HOMO Offset
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- Liu, Yanfeng (författare)
- Linköpings universitet,Biomolekylär och Organisk Elektronik,Tekniska fakulteten
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- Zhang, Jianyun (författare)
- Chinese Acad Sci, Peoples R China; Univ Chinese Acad Sci, Peoples R China
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- Zhou, Guanqing (författare)
- Shanghai Jiao Tong Univ, Peoples R China
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- Liu, Feng (författare)
- Shanghai Jiao Tong Univ, Peoples R China
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- Zhu, Xiaozhang (författare)
- Chinese Acad Sci, Peoples R China; Univ Chinese Acad Sci, Peoples R China
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- Zhang, Fengling (författare)
- Linköpings universitet,Biomolekylär och Organisk Elektronik,Tekniska fakulteten
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(creator_code:org_t)
- 2020-06-24
- 2020
- Engelska.
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Ingår i: The Journal of Physical Chemistry C. - : AMER CHEMICAL SOC. - 1932-7447 .- 1932-7455. ; 124:28, s. 15132-15139
- Relaterad länk:
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https://liu.diva-por... (primary) (Raw object)
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https://pubs.acs.org...
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https://urn.kb.se/re...
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https://doi.org/10.1...
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Abstract
Ämnesord
Stäng
- The record high photoinduced current and power conversion efficiencies of organic solar cells (OSCs) should be attributed to the significant contribution of non-fullerene electron acceptors via hole transfer to electron donors and/or a pronounced decrease in energy losses for exciton dissociation by aligned highest occupied molecular orbitals (HOMOs) or lowest unoccupied molecular orbitals (LUMOs). However, the hole transfer mechanism in those highly efficient non-fullerene OSCs with small HOMO offsets has not been extensively studied and fully understood, yet. Herein, we comparatively study the hole transfer kinetics in two OSCs with a positive (0.05 eV) and a negative (-0.07 eV) HOMO offset (Delta HOMO) based on polymer donor PTQ10 paired with non-fullerene acceptors ZITI-C or ZITI-N. Short-circuit current densities (J(sc)) of 20.42 and 12.81 mA cm(-2) are achieved in the OSCs based on PTQ10:ZITI-C (Delta HOMO = 0.05 eV) and PTQ10:ZITI-N (Delta HOMO = -0.07 eV) with an optimized donor (D):acceptor (A) ratio of 1:1, respectively, despite the small and even negative Delta HOMO. Results from time-resolved transient absorption spectroscopy show slower hole transfer (14.3 ps) in PTQ10:ZITI-N than that (3.7 ps) in PTQ10:ZITI-C. To understand the decent J(sc) value in the OSCs of PTQ10:ZITI-N, the temperature and electric field dependences of hole transfer are investigated in low-donor-content OSCs (D:A ratio of 1:9) in which photocurrent is dominated by the contribution via hole transfer from ZITI-N to PTQ10. Devices based on PTQ10:ZITI-C and PTQ10:ZITI-N show similar free charge generation behavior as a function of temperature, whereas the external quantum efficiencies of the PTQ10:ZITI-N device exhibit a much stronger bias dependence than that of PTQ10:ZITI-C, which suggests that the electric field facilitates exciton dissociation in PTQ10:ZITI-N where the energetic driving force alone cannot efficiently dissociate excitons.
Ämnesord
- NATURVETENSKAP -- Fysik -- Den kondenserade materiens fysik (hsv//swe)
- NATURAL SCIENCES -- Physical Sciences -- Condensed Matter Physics (hsv//eng)
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