Small-bandgap π-conjugated polymers are an important class of materials possessing significant potentials for their broad applications in organic electronics. Incorporating a quinoid structure into the polymer backbone is a powerful...

Controlling self-organization and morphology of chemical architectures is an essential challenge for the search of higher energy-conversion efficiencies in a variety of optoelectronic devices. Here, we report a highly ordered donor/acceptor functional material, which has been obtained using the principle of ionic self-assembly. Initially, an electron donor π-extended tetrathiafulvalene and an electron acceptor perylene-bisimide were self-organized separately obtaining n-and p-nanofibers at the same scale. These complementary n-and p-nanofibers are endowed with ionic groups with opposite charges on their surfaces. The synergic interactions establish periodic alignments between both nanofibers resulting in a material with segregated and alternately stacked donor/acceptor nanodomains. Photoconductivity measurements show values for these n/p-co-assembled materials up to 0.8 cm 2 V -1 s -1 , confirming the effectiveness in the design of these heterojunction structures. This easy methodology offers great possibilities to achieve highly ordered n/p-materials for potential applications in different areas such as optoelectonics and photovoltaic.The control on the organization and morphology of organic materials at different scales is an essential challenge in current science. 1 In particular, organic materials employed for obtaining efficient photovoltaic devices require a controlled segregation of electron donor/acceptor domains in the active layers because transport of the photo-generated charge carriers occurs through these domains to the electrodes. This control over the organization of nanostructured domains at the same length scale generally results in an increase in conductivity or photoconductivity values. 2 One of the approaches to prepare optoelectronic materials for photon-energy conversion is the use of covalent donor-acceptor (D-A) dyads. In this context, a great variety of D-A dyads have been reported with an elaborated synthetic strategy. 3-5 These D-A dyads provide nanoscale D-A heterojunctions with different morphologies such as fibrous, 3 tubular 4 or liquid crystals, to name a few. 5 On the other hand, supramolecular chemistry is gaining attention, when compared to covalent methodologies, due to its higher versatility and easier ensembles preparation. From small molecules and through weak and non-covalent intermolecular interactions such as hydrogen bonding, metal coordination, hydrophobic forces, van der Waals forces, π-π stacking and electrostatic interactions, it is possible to reach highly ordered structures at the nano and mesoscales. 6

We report a systematic study of organic photovoltaic cells using novel spiro-acetalized and (thio)acetalized [60]fullerene monoadducts bearing five- to seven-membered rings.

N-type (electron-transporting) semiconducting polymers are essential materials for the development of truly plastic electronic devices. Here, we synthesized for the first time dithiazolylthienothiophene bisimide (TzBI), as a new family for imide-based electron-deficient πconjugated systems, and semiconducting polymers by incorporating TzBI into the π-conjugated backbone as the building unit. The TzBI-based polymers are found to have deep frontier molecular orbital energy levels and wide optical bandgaps compared to the dithienylthienothiophene bisimide (TBI) counterpart. It is also found that TzBI can promote the π-π intermolecular interactions of the polymer backbones relative to TBI most probably because the thiazole ring, which replaced the thiophene ring, at the end of the framework gives a more coplanar backbone. In fact, TzBIbased polymers function as the n-type semiconducting material in both organic field-effect transistor (OFET) and organic photovoltaic (OPV) devices. Notably, one of the TzBI-based polymers provides a power conversion efficiency of 3.3% in the all-polymer OPV device, which could be high for a low-molecular weight polymer (<10 kDa). Interestingly, while many of the ntype semiconducting polymers utilized in OPVs have narrow bandgaps, the TzBI-based polymers have wide bandgaps. This is highly beneficial for complementing the visible to near-IR light absorption range when blended with p-type narrow bandgap polymers that have been widely developed in the last decade. The results demonstrate great promise and possibility of TzBI as the building unit for n-type semiconducting polymers. ASSOCIATED CONTENT Supporting Information.

Over the past two decades, the charge carrier mobility of πconjugated polymers has vastly improved. This has been mostly achieved by increasing the π−π stacking ability of the polymers through advanced molecular design, thereby improving "interchain" charge carrier transport. However, the rational design of π-conjugated polymers for improving "intrachain" charge carrier transport along the backbone still remains a formidable challenge. Here, we show the synthesis of a new π-conjugated polymer based on a quinoidal bithiophene moiety (PSP4T), which interestingly, was found to have significantly extended π-electron delocalization along the backbone compared to its isomer (PBTD4T), although these polymers have an identical basic structure. Importantly, despite the similar π−π stacking structure, PSP4T demonstrated transistor mobilities of around 1−2.5 cm 2 V −1 s −1 that are 1−2 orders of magnitude higher than that of PBTD4T. On the basis of further investigations of energetic disorder and theoretical simulations, the higher mobility in PSP4T than in PBTD4T is most likely attributed to the remarkably higher intrachain charge carrier transport, which originates in the highly extended π-electron delocalization. We believe that our study can provide new guidelines for the design of πconjugated polymers with high intrachain charge carrier transport.