- Thieno[3,4-b ]thiophene acceptors with alkyl, aryl, perfluoroalkyl, and perfluorophenyl pendants for donor-acceptor low bandgap polymers
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We report the design, synthesis, and characterization of a series of thieno[3,4-b]thiophene acceptor blocks with octyl (T8), phenyl (TP), perfluorooctyl (TF8), and perfluorophenyl (TFP) side groups. Their subsequent copolymerization with dithienylbenzodithiophene by direct arylation polymerization afforded novel low bandgap poly(thienothiophene-alt- dithienylbenzodithiophene) (PTB) polymers. The strongly electron withdrawing TF8 and TFP groups were shown to significantly lower both EHOMO and ELUMO levels and gave computed copolymer ground-to-excited state dipole changes (Δμge) that were relatively higher than for the nonfluorinated analogues. These materials show favorably aligned energy levels relative to conventional fullerene-type acceptors, which should allow them to perform well in organic photovoltaics.
- Homyak, Patrick D.,Tinkham, Jonathan,Lahti, Paul M.,Coughlin, E. Bryan
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- Indacenodithiophene-based small-molecule donor with strong crystallinity for efficient organic solar cells
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Two indacenodithiophene (IDT)-based small-molecule analogues (IDBTandIDBT-Cl) are designed as donor materials for organic solar cells. Relative to the amorphousIDBT-Cl, theIDBTwith strong crystallinity shows overall better photovoltaic performance when blended with a Y6 acceptor. The results demonstrate the great potential of IDT units in designing efficient small-molecule donors.
- Zheng, Yan,Bao, Sunan,Yang, Hang,Fan, Hongyu,Fan, Dongdong,Cui, Chaohua,Li, Yongfang
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p. 10767 - 10770
(2021/10/20)
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- Enhanced and controllable open-circuit voltage using 2D-conjugated benzodithiophene (BDT) homopolymers by alkylthio substitution
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In this study, we explore the effects of alkylthiophene (T) and alkylthiothiophene (T-S) substituents on the benzo[1,2-b;4,5-b′]dithiophene (BDT) unit by comparing the BDTT homopolymer (PBDTT), the BDTT-alt-BDTT-S copolymer (PBDTT-BDTT-S), and the BDTT-S homopolymer (PBDTT-S) in terms of UV-visible absorption spectra, cyclic voltammetry (CV) results, computational calculations, and experimental results. The T-S substituent increased the hole mobility of the polymer and down-shifted the highest occupied molecular orbital (HOMO) energy level of the polymer, leading to slight red-shifting of the absorption spectrum. The organic photovoltaic (OPV) cells based on PBDTT-S as a donor and [6,6]-phenyl-C71-butylic acid methyl ester (PC71BM) as an acceptor demonstrated a high power conversion efficiency (PCE) of 7.05% under AM 1.5G illumination (100 mW cm-2). To the best of our knowledge, this PCE value is one of the highest values reported for homopolymer donor-based OPVs. Compared to the well-known P3HT homopolymer, which shows a similar absorption profile, PBDTT-S is a promising candidate for organic photodiodes.
- Kim, Ji-Hoon,Park, Jong Baek,Yoon, Sung Cheol,Jung, In Hwan,Hwang, Do-Hoon
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p. 2170 - 2177
(2016/03/19)
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