Hole transport in low-donor-content organic solar cells

Organic solar cells with an electron donor diluted in a fullerene matrix have a reduced density of donor-fullerene contacts, resulting in decreased free-carrier recombination and increased open-circuit voltages. However, the low donor concentration prevents the formation of percolation pathways for...

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Main Authors: Spoltore, D, Hofacker, A, Benduhn, J, Ullbrich, S, Nyman, M, Zeika, O, Schellhammer, S, Fan, Y, Ramirez, I, Barlow, S, Riede, M, Marder, SR, Ortmann, F, Vandewal, K
Format: Journal article
Language:English
Published: American Chemical Society 2018
_version_ 1797070549217705984
author Spoltore, D
Hofacker, A
Benduhn, J
Ullbrich, S
Nyman, M
Zeika, O
Schellhammer, S
Fan, Y
Ramirez, I
Barlow, S
Riede, M
Marder, SR
Ortmann, F
Vandewal, K
author_facet Spoltore, D
Hofacker, A
Benduhn, J
Ullbrich, S
Nyman, M
Zeika, O
Schellhammer, S
Fan, Y
Ramirez, I
Barlow, S
Riede, M
Marder, SR
Ortmann, F
Vandewal, K
author_sort Spoltore, D
collection OXFORD
description Organic solar cells with an electron donor diluted in a fullerene matrix have a reduced density of donor-fullerene contacts, resulting in decreased free-carrier recombination and increased open-circuit voltages. However, the low donor concentration prevents the formation of percolation pathways for holes. Notwithstanding, high (>75%) external quantum efficiencies can be reached, suggesting an effective hole-transport mechanism. Here, we perform a systematic study of the hole mobilities of 18 donors, diluted at ∼6 mol % in C60, with varying frontier energy level offsets and relaxation energies. We find that hole transport between isolated donor molecules occurs by long-range tunneling through several fullerene molecules, with the hole mobilities being correlated to the relaxation energy of the donor. The transport mechanism presented in this study is of general relevance to bulk heterojunction organic solar cells where mixed phases of fullerene containing a small fraction of a donor material or vice versa are present as well.
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spelling oxford-uuid:5b5b9e82-a375-469b-8a2c-678bd6a0be7a2022-03-26T17:21:40ZHole transport in low-donor-content organic solar cellsJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:5b5b9e82-a375-469b-8a2c-678bd6a0be7aEnglishSymplectic Elements at OxfordAmerican Chemical Society2018Spoltore, DHofacker, ABenduhn, JUllbrich, SNyman, MZeika, OSchellhammer, SFan, YRamirez, IBarlow, SRiede, MMarder, SROrtmann, FVandewal, KOrganic solar cells with an electron donor diluted in a fullerene matrix have a reduced density of donor-fullerene contacts, resulting in decreased free-carrier recombination and increased open-circuit voltages. However, the low donor concentration prevents the formation of percolation pathways for holes. Notwithstanding, high (>75%) external quantum efficiencies can be reached, suggesting an effective hole-transport mechanism. Here, we perform a systematic study of the hole mobilities of 18 donors, diluted at ∼6 mol % in C60, with varying frontier energy level offsets and relaxation energies. We find that hole transport between isolated donor molecules occurs by long-range tunneling through several fullerene molecules, with the hole mobilities being correlated to the relaxation energy of the donor. The transport mechanism presented in this study is of general relevance to bulk heterojunction organic solar cells where mixed phases of fullerene containing a small fraction of a donor material or vice versa are present as well.
spellingShingle Spoltore, D
Hofacker, A
Benduhn, J
Ullbrich, S
Nyman, M
Zeika, O
Schellhammer, S
Fan, Y
Ramirez, I
Barlow, S
Riede, M
Marder, SR
Ortmann, F
Vandewal, K
Hole transport in low-donor-content organic solar cells
title Hole transport in low-donor-content organic solar cells
title_full Hole transport in low-donor-content organic solar cells
title_fullStr Hole transport in low-donor-content organic solar cells
title_full_unstemmed Hole transport in low-donor-content organic solar cells
title_short Hole transport in low-donor-content organic solar cells
title_sort hole transport in low donor content organic solar cells
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