@article{Marin-Beloqui:2022:10.1021/acs.jpcc.1c10378,
author = {Marin-Beloqui, J and Zhang, G and Guo, J and Shaikh, J and Wohrer, T and Hosseini, SM and Sun, B and Shipp, J and Auty, AJ and Chekulaev, D and Ye, J and Chin, Y-C and Sullivan, MB and Mozer, AJ and Kim, J-S and Shoaee, S and Clarke, TM},
doi = {10.1021/acs.jpcc.1c10378},
journal = {The Journal of Physical Chemistry C: Energy Conversion and Storage, Optical and Electronic Devices, Interfaces, Nanomaterials, and Hard Matter},
pages = {2708--2719},
title = {Insight into the origin of trapping in polymer/fullerene blends with a systematic alteration of the fullerene to higher adducts},
url = {http://dx.doi.org/10.1021/acs.jpcc.1c10378},
volume = {126},
year = {2022}
}

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TY  - JOUR
AB  - 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-yl thiazolo 5,4-d thiazole)-2,5diyl] (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 μs-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
AU  - Marin-Beloqui,J
AU  - Zhang,G
AU  - Guo,J
AU  - Shaikh,J
AU  - Wohrer,T
AU  - Hosseini,SM
AU  - Sun,B
AU  - Shipp,J
AU  - Auty,AJ
AU  - Chekulaev,D
AU  - Ye,J
AU  - Chin,Y-C
AU  - Sullivan,MB
AU  - Mozer,AJ
AU  - Kim,J-S
AU  - Shoaee,S
AU  - Clarke,TM
DO  - 10.1021/acs.jpcc.1c10378
EP  - 2719
PY  - 2022///
SN  - 1932-7447
SP  - 2708
TI  - Insight into the origin of trapping in polymer/fullerene blends with a systematic alteration of the fullerene to higher adducts
T2  - The Journal of Physical Chemistry C: Energy Conversion and Storage, Optical and Electronic Devices, Interfaces, Nanomaterials, and Hard Matter
UR  - http://dx.doi.org/10.1021/acs.jpcc.1c10378
UR  - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000766226700040&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
UR  - https://pubs.acs.org/doi/10.1021/acs.jpcc.1c10378
UR  - http://hdl.handle.net/10044/1/98285
VL  - 126
ER  - 

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