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Conjugated binary copolymers containing an electron donor (D) and acceptor (A) in the repeating unit have been extensively studied due to their excellent charge transport properties. Moreover, conjugated terpolymers containing a third monomer in addition to the two D and A monomers have been recognized to exhibit finely tuned properties relative to the binary D-A copolymer. Diketopyrrolopyrrole (DPP)–based conjugated regular terpolymers (CRTs) containing two different electron donor monomers were synthesized herein to exploit the advantages of the terpolymer. Two terpolymers were synthesized by using bithiophene and pyrene as third monomers. Compared to the reference copolymer, poly[3-(5-(benzo[1,2-b:4,5-b']dithiophen-2-yl)thiophen-2-yl)-2,5-bis(2-decyltetradecyl)-6-(thiophen-2-yl)-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione] (PDPPBDT), the new terpolymers exhibited distinct physical properties, absorption properties, and electronic energy levels. The terpolymers were employed in thin film transistors (TFTs) and polymer solar cells (PSCs) and the device performance was studied. The highest mobility achieved for the TFT devices was close to 1.0 cm 2  V −1  s −1 and was obtained with the PDPPBTBDT terpolymer film as the active layer, whereas the mobilities of the TFTs employing the PDPPPYBDT and PDPPBDT polymers were relatively low. In contrast with the TFT device results, the PSC fabricated with PDPPPYBDT:PC 71 BM showed the highest power conversion efficiency (PCE) of 4.46% due to the relatively high V oc and J sc . The results of this study confirmed that the use of a regular terpolymer structure permits fine adjustment of the light absorption range, the molecular energy levels, and the film morphology of the polymer, in turn influencing the device performance of TFTs or PSCs. [ABSTRACT FROM AUTHOR]

ABSTRACT We demonstrate a fully conjugated donor-acceptor-donor (D-A-D) triblock copolymer, PBDTT-PNDIBT-PBDTT, which contains PBDTT as the donor block and PNDIBT as the acceptor block. The polymer was synthesized by end-capping each block with a reactive unit, followed by condensation copolymerization between the two blocks. The physical, optical, and electrochemical properties of the polymer were investigated by comparing those of donor- and acceptor-homopolymers (i.e., PBDTT and PNDIBT), which are the oligomeric monomers, and their blends. On using the newly synthesized block copolymer, ambipolar charge transport behavior was observed in the corresponding thin-film transistor, and the behavior was compared to that of blend film of donor- and acceptor-homopolymers. Owing to the presence of donor and acceptor blocks in a single polymer chain, it was found that the triblock copolymer can store two-level information; the ability to store this information is one of the most intriguing challenges in memory applications. In this study, we confirmed the potential of the triblock copolymer in achieving distinct two-stage data storage by utilizing the ambipolar charge trapping phenomenon, which is expected in donor and acceptor containing random and block copolymers in a thin-film transistor. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 3223-3235 [ABSTRACT FROM AUTHOR]

We designed and synthesized two kinds of spirobifluorene (SP)-based acceptor–donor–acceptor (A–D–A)-type acceptor materials, denoted by SP-IC and SP-TCF, which have an A–D–A structure consisting of a 3D tetrathienospirobifluorene donor core and 2-(3-oxo-2,3-dihydro-1 H -inden-1-ylidene)malononitrile (IC) or 2-(3-cyano-4,5,5-trimethylfuran-2(5 H )-ylidene)malononitrile (TCF) acceptors as terminal units, respectively. Their LUMO levels (−3.91 eV for SP-IC and −3.97 eV for SP-TCF) are suitable as n-type molecules for PTB7-Th-based polymer solar cells. However, their morphologies in blend films with a conjugated donor polymer, Poly([2,6′-4,8-di(5-ethylhexylthienyl)benzo[1,2-b;3,3-b]dithiophene]{3-fluoro-2[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl}) (PTB7-Th), exhibited considerable differences. The PTB7-Th:SP-IC blend film exhibited a better-defined nanophase-separated morphology than PTB7-Th:SP-TCF blend film. The corresponding bulk heterojunction polymer solar cell based on PTB7-Th:SP-IC showed four times higher power conversion efficiency (PCE = 4.50%) than that of PTB7-Th:SP-TCF. The higher PCE was well explained by investigating the morphology, which was affected by the surface energy of the acceptor molecules at the donor–acceptor interface. [ABSTRACT FROM AUTHOR]