Jose Marin-Beloqui, Guanran Zhang, Junjun Guo, Jordan Shaikh, Thibaut Wohrer, Seyed Mehrdad Hosseini, Bowen Sun, James Shipp, Alexander J. Auty, Dimitri Chekulaev, Jun Ye, Yi-Chun Chin, Michael B. Sullivan, Attila J. Mozer, Ji-Seon Kim, Safa Shoaee, Tracey M. Clarke
- The bimolecular recombination characteristics of conjugated polymer poly[(4,4'-bis(2-ethylhexyl)dithieno[3,2-b:2',3'-d]silole)-2,6-diyl-alt-(2,5-bis 3-tetradecylthiophen-2-y1 thiazolo 5,4-d thiazole)-2,5diy1] (PDTSiTTz) blended with the fullerene series PC60BM, ICMA, ICBA, and ICTA have been investigated using microsecond and femtosecond transient absorption spectroscopy, in conjunction with electroluminescence measurements and ambient photoemission spectroscopy. The non-Langevin polymer PDTSiTTz allows an inspection of intrinsic bimolecular recombination rates uninhibited by diffusion, while the low oscillator strengths of fullerenes allow polymer features to dominate, and we compare our results to those of the well-known polymer Si-PCPDTBT. Using mu s-TAS, we have shown that the trap -limited decay dynamics of the PDTSiTTz polaron becomes progressively slower across the fullerene series, while those of Si-PCPDTBT are invariant. Electroluminescence measurements showed an unusual double peak in pristine PDTSiTTz, attributed to a lowThe bimolecular recombination characteristics of conjugated polymer poly[(4,4'-bis(2-ethylhexyl)dithieno[3,2-b:2',3'-d]silole)-2,6-diyl-alt-(2,5-bis 3-tetradecylthiophen-2-y1 thiazolo 5,4-d thiazole)-2,5diy1] (PDTSiTTz) blended with the fullerene series PC60BM, ICMA, ICBA, and ICTA have been investigated using microsecond and femtosecond transient absorption spectroscopy, in conjunction with electroluminescence measurements and ambient photoemission spectroscopy. The non-Langevin polymer PDTSiTTz allows an inspection of intrinsic bimolecular recombination rates uninhibited by diffusion, while the low oscillator strengths of fullerenes allow polymer features to dominate, and we compare our results to those of the well-known polymer Si-PCPDTBT. Using mu s-TAS, we have shown that the trap -limited decay dynamics of the PDTSiTTz polaron becomes progressively slower across the fullerene series, while those of Si-PCPDTBT are invariant. Electroluminescence measurements showed an unusual double peak in pristine PDTSiTTz, attributed to a low energy intragap charge transfer state, likely interchain in nature. Furthermore, while the pristine PDTSiTTz showed a broad, low-intensity density of states, the ICBA and ICTA blends presented a virtually identical DOS to Si-PCPDTBT and its blends. This has been attributed to a shift from a delocalized, interchain highest occupied molecular orbital (HOMO) in the pristine material to a dithienosilole-centered HOMO in the blends, likely a result of the bulky fullerenes increasing interchain separation. This HOMO localization had a side effect of progressively shifting the polymer HOMO to shallower energies, which was correlated with the observed decrease in bimolecular recombination rate and increased "trap" depth. However, since the density of tail states remained the same, this suggests that the traditional viewpoint of "trapping" being dominated by tail states may not encompass the full picture and that the breadth of the DOS may also have a strong influence on bimolecular recombination.…
MetadatenAuthor details: | Jose Marin-Beloqui, Guanran ZhangORCiD, Junjun Guo, Jordan Shaikh, Thibaut Wohrer, Seyed Mehrdad HosseiniORCiDGND, Bowen SunORCiDGND, James Shipp, Alexander J. Auty, Dimitri Chekulaev, Jun Ye, Yi-Chun ChinORCiD, Michael B. Sullivan, Attila J. Mozer, Ji-Seon Kim, Safa ShoaeeORCiDGND, Tracey M. Clarke |
---|
DOI: | https://doi.org/10.1021/acs.jpcc.1c10378 |
---|
ISSN: | 1932-7447 |
---|
ISSN: | 1932-7455 |
---|
Pubmed ID: | https://pubmed.ncbi.nlm.nih.gov/35573707 |
---|
Title of parent work (English): | Journal of physical chemistry C |
---|
Publisher: | American Chemical Society |
---|
Place of publishing: | Washington |
---|
Publication type: | Article |
---|
Language: | English |
---|
Date of first publication: | 2022/01/31 |
---|
Publication year: | 2022 |
---|
Release date: | 2024/06/25 |
---|
Volume: | 126 |
---|
Issue: | 5 |
---|
Number of pages: | 12 |
---|
First page: | 2708 |
---|
Last Page: | 2719 |
---|
Funding institution: | EPSRC project [EP/N026411/1]; Alexander von Humboldt Foundation (Sofja; Kovalevskaja prize); UK EPSRC ATIP Programme Grant [EP/T028513/1];; Global Research Laboratory Program of the Korean National Research; Foundation (NRF) - Ministry of Science, ICT & Future Planning; [NRF2017K1A1A2013153] |
---|
Organizational units: | Mathematisch-Naturwissenschaftliche Fakultät / Institut für Physik und Astronomie |
---|
DDC classification: | 5 Naturwissenschaften und Mathematik / 53 Physik / 530 Physik |
---|
Peer review: | Referiert |
---|
Publishing method: | Open Access / Hybrid Open-Access |
---|
License (German): | CC-BY - Namensnennung 4.0 International |
---|