Origin of poor photovoltaic performance of bis(tetracyanoantrathiophene) non-fullerene acceptor

Origin of poor photovoltaic performance of bis(tetracyanoantrathiophene) non-fullerene acceptor

Light-induced EPR and out-of-phase electron spin echo techniques were applied to identify the origin of low photovoltaic performance of novel non-fullerene antrathiophene-based acceptor 2,2′-[2,2′-(9,9-dioctyl-9H-fluorene-2,7-diyl)bis(anthra[2,3-b]thiophene-5,10-diylidene)]tetrapropanedinitrile (AT1...

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Bibliographic Details
Published in:Chemical physics Vol. 546; p. 111162
Main Authors: Kobeleva, E.S., Popov, A.A., Baranov, D.S., Uvarov, M.N., Nevostruev, D.A., Degtyarenko, K.M., Gadirov, R.M., Sukhikh, A.S., Kulik, L.V.
Format: Journal Article
Language:English
Published: Elsevier B.V 01-06-2021
Subjects:
Electron spin echo
EPR spectroscopy
Fullerenes
Mobility
Organic photovoltaics
Recombination
Fullerenes
Mobility
Recombination
Organic photovoltaics
EPR spectroscopy
Electron spin echo
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Summary:Light-induced EPR and out-of-phase electron spin echo techniques were applied to identify the origin of low photovoltaic performance of novel non-fullerene antrathiophene-based acceptor 2,2′-[2,2′-(9,9-dioctyl-9H-fluorene-2,7-diyl)bis(anthra[2,3-b]thiophene-5,10-diylidene)]tetrapropanedinitrile (AT1), compared to conventional fullerene acceptors. These techniques revealed that average trapping energy of electrons in PCDTBT/AT1 blend is higher than that in the blends of PCDTBT with fullerene acceptors, while the distance of the initial photo-induced electron transfer is decreased. These two effects are suggested to enhance the efficiency of geminate recombination in PCDTBT/AT1 blend and reduce the yield of free charges, which is supposed to be the main reason for poor OPV performance of AT1-containing blends. Low electron mobility μe = 3.5 *10-6 cm2V-1s−1 is estimated for AT1 from photo-CELIV experiment. Strong localization of the electrons on terminal acceptor units of AT1 consistently explains both efficient geminate recombination in blends of antrathiophene-based acceptor with polymer donors and low electron mobility in AT1.
ISSN:0301-0104
DOI:10.1016/j.chemphys.2021.111162