Ultrafast charge dynamics in dilute-donor versus highly intermixed TAPC:c60 organic solar cell blends
Elucidating the interplay between film morphology, photophysics, and device performance of bulk heterojunction (BHJ) organic photovoltaics remains challenging. Here, we use the well-defined morphology of vapor-deposited di-[4-(N,N-di-p-tolyl-amino)-phenyl]cyclohexane (TAPC):C60 blends to address cha...
| Main Authors: | , , , , , , , , |
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| Format: | Journal article |
| Language: | English |
| Published: |
American Chemical Society
2020
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| _version_ | 1797091890106990592 |
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| author | Moore, GJ Causa', M Martinez Hardigree, JF Karuthedath, S Ramirez, I Jungbluth, A Laquai, F Riede, M Banerji, N |
| author_facet | Moore, GJ Causa', M Martinez Hardigree, JF Karuthedath, S Ramirez, I Jungbluth, A Laquai, F Riede, M Banerji, N |
| author_sort | Moore, GJ |
| collection | OXFORD |
| description | Elucidating the interplay between film morphology, photophysics, and device performance of bulk heterojunction (BHJ) organic photovoltaics remains challenging. Here, we use the well-defined morphology of vapor-deposited di-[4-(N,N-di-p-tolyl-amino)-phenyl]cyclohexane (TAPC):C60 blends to address charge generation and recombination by transient ultrafast spectroscopy. We gain relevant new insights to the functioning of dilute-donor (5% TAPC) fullerene-based BHJs compared to molecularly intermixed systems (50% TAPC). First, we show that intermolecular charge-transfer (CT) excitons in the C60 clusters of dilute BHJs rapidly localize to Frenkel excitons prior to dissociating at the donor:acceptor interface. Thus, both Frenkel and CT excitons generate photocurrent over the entire fullerene absorption range. Second, we selectively monitor interfacial and bulk C60 clusters via their electro-absorption, demonstrating an energetic gradient that assists free charge generation. Third, we identify a fast (<1 ns) recombination channel, whereby free electrons recombine with trapped holes on isolated TAPC molecules. This can harm the performance of dilute solar cells, unless the electrons are rapidly extracted in efficient devices. |
| first_indexed | 2024-03-07T03:38:49Z |
| format | Journal article |
| id | oxford-uuid:bd3272c2-f9c8-4ca7-b939-187386c44a95 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T03:38:49Z |
| publishDate | 2020 |
| publisher | American Chemical Society |
| record_format | dspace |
| spelling | oxford-uuid:bd3272c2-f9c8-4ca7-b939-187386c44a952022-03-27T05:29:56ZUltrafast charge dynamics in dilute-donor versus highly intermixed TAPC:c60 organic solar cell blendsJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:bd3272c2-f9c8-4ca7-b939-187386c44a95EnglishSymplectic ElementsAmerican Chemical Society2020Moore, GJCausa', MMartinez Hardigree, JFKaruthedath, SRamirez, IJungbluth, ALaquai, FRiede, MBanerji, NElucidating the interplay between film morphology, photophysics, and device performance of bulk heterojunction (BHJ) organic photovoltaics remains challenging. Here, we use the well-defined morphology of vapor-deposited di-[4-(N,N-di-p-tolyl-amino)-phenyl]cyclohexane (TAPC):C60 blends to address charge generation and recombination by transient ultrafast spectroscopy. We gain relevant new insights to the functioning of dilute-donor (5% TAPC) fullerene-based BHJs compared to molecularly intermixed systems (50% TAPC). First, we show that intermolecular charge-transfer (CT) excitons in the C60 clusters of dilute BHJs rapidly localize to Frenkel excitons prior to dissociating at the donor:acceptor interface. Thus, both Frenkel and CT excitons generate photocurrent over the entire fullerene absorption range. Second, we selectively monitor interfacial and bulk C60 clusters via their electro-absorption, demonstrating an energetic gradient that assists free charge generation. Third, we identify a fast (<1 ns) recombination channel, whereby free electrons recombine with trapped holes on isolated TAPC molecules. This can harm the performance of dilute solar cells, unless the electrons are rapidly extracted in efficient devices. |
| spellingShingle | Moore, GJ Causa', M Martinez Hardigree, JF Karuthedath, S Ramirez, I Jungbluth, A Laquai, F Riede, M Banerji, N Ultrafast charge dynamics in dilute-donor versus highly intermixed TAPC:c60 organic solar cell blends |
| title | Ultrafast charge dynamics in dilute-donor versus highly intermixed TAPC:c60 organic solar cell blends |
| title_full | Ultrafast charge dynamics in dilute-donor versus highly intermixed TAPC:c60 organic solar cell blends |
| title_fullStr | Ultrafast charge dynamics in dilute-donor versus highly intermixed TAPC:c60 organic solar cell blends |
| title_full_unstemmed | Ultrafast charge dynamics in dilute-donor versus highly intermixed TAPC:c60 organic solar cell blends |
| title_short | Ultrafast charge dynamics in dilute-donor versus highly intermixed TAPC:c60 organic solar cell blends |
| title_sort | ultrafast charge dynamics in dilute donor versus highly intermixed tapc c60 organic solar cell blends |
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