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Developing low‐cost and high‐performance n‐type polymer semiconductors is essential to accelerate the application of organic thermoelectrics (OTEs). To achieve this objective, it is critical to design strong electron‐deficient building blocks with simple structure and easy synthesis, which are essential for the development of n‐type polymer semiconductors. Herein, we synthesized two cyano‐functionalized highly electron‐deficient building blocks, namely 3,6‐dibromopyrazine‐2‐carbonitrile (CNPz) and 3,6‐Dibromopyrazine‐2,5‐dicarbonitrile (DCNPz), which feature simple structures and facile synthesis. CNPz and DCNPz can be obtained via only one‐step reaction and three‐step reactions from cheap raw materials, respectively. Based on CNPz and DCNPz, two acceptor–acceptor (A–A) polymers, P(DPP‐CNPz) and P(DPP‐DCNPz) are successfully developed, featuring deep‐positioned lowest unoccupied molecular orbital (LUMO) energy levels, which are beneficial to n‐type organic thin‐film transistors (OTFTs) and OTEs performance. An optimal unipolar electron mobility of 0.85 and 1.85 cm2 V−1 s−1 is obtained for P(DPP‐CNPz) and P(DPP‐DCNPz), respectively. When doped with N‐DMBI, P(DPP‐CNPz) and P(DPP‐DCNPz) show high n‐type electrical conductivities/power factors of 25.3 S cm−1/41.4 μW m−1 K−2, and 33.9 S cm−1/30.4 μW m−1 K−2, respectively. Hence, the cyano‐functionalized pyrazine CNPz and DCNPz represent a new class of structurally simple, low‐cost and readily accessible electron‐deficient building block for constructing n‐type polymer semiconductors. [ABSTRACT FROM AUTHOR]

Developing high‐performance but low‐cost n‐type polymers remains a significant challenge in the commercialization of organic field‐effect transistors (OFETs). To achieve this objective, it is essential to design the key electron‐deficient units with simple structures and facile preparation processes, which can facilitate the production of low‐cost n‐type polymers. Herein, by sequentially introducing fluorine and cyano functionalities onto trans‐1,3‐butadiene, we developed a series of structurally simple but highly electron‐deficient building blocks, namely 1,4‐dicyano‐butadiene (CNDE), 3‐fluoro‐1,4‐dicyano‐butadiene (CNFDE), and 2,3‐difluoro‐1,4‐dicyano‐butadiene (CNDFDE), featuring a highly coplanar backbone and deep‐positioned lowest unoccupied molecular orbital (LUMO) energy levels (−3.03–4.33 eV), which render them highly attractive for developing n‐type semiconducting polymers. Notably, all these electron‐deficient units can be easily accessed by a two‐step high‐yield synthetic procedure from low‐cost raw materials, thus rendering them highly promising candidates for commercial applications. Upon polymerization with diketopyrrolopyrrole (DPP), three copolymers were developed that demonstrated unipolar n‐type transport characteristics in OFETs with the highest electron mobility of >1 cm2 V−1 s−1. Hence, CNDE, CNFDE, and CNDFDE represent a class of novel, simple, and efficient electron‐deficient units for constructing low‐cost n‐type polymers, thereby providing valuable insight for OFET applications. [ABSTRACT FROM AUTHOR]

Designing n‐type polymers with high electrical conductivity remains a major challenge for organic thermoelectrics (OTEs). Herein, by devising a novel selenophene‐based electron‐deficient building block, the pronounced advantages of selenium substitution in simultaneously enabling advanced n‐type polymers is demonstrated with high mobility (≈2 orders of magnitude higher versus their sulfur‐based analogues due to both intensified intra‐ and inter‐chain interactions) and much improved n‐doping efficiency (enabled by the largely lowered LUMO level with a ≈0.2 eV margin) of the resulting polymers. Via side chain optimization and donor engineering, the selenium‐substituted polymer, f‐BSeI2TEG‐FT, achieves a highest conductivity of 103.5 S cm−1 and power factor of 70.1 µW m−1 K−2, which are among the highest values reported in literature for n‐type polymers, and f‐BSeI2TEG‐FT greatly outperformed the sulfur‐based analogue polymer by 40% conductivity increase. These results demonstrate that selenium substitution is a very effective strategy for improving n‐type performance and provide important structure‐property correlations for developing high‐performing n‐type OTE materials. [ABSTRACT FROM AUTHOR]

The development of high‐performance n‐type polymer semiconductors is powered by the design and synthesis of electron‐deficient building blocks with optimized physicochemical properties. By meticulously installing an imide group onto fluorene and its cyanated derivative, we report here two very electron‐deficient building blocks, imide‐functionalized fluorenone (FOI) and its cyanated derivative (FCNI), both featuring a deep‐lying lowest unoccupied molecular orbital energy level down to −4.05 eV and highly coplanar framework, endowing them ideal units for constructing n‐type polymers. Thus, a series of polymers are built from them, exhibiting unipolar n‐type transport character with a highest electron mobility of 0.11 cm2 V−1 s−1. Hence, FOI and FCNI offer a remarkable platform for accessing high‐performance n‐type polymers and the imide functionalization of appropriate (hetero)arenes is a powerful strategy for developing polymers with deep‐lying LUMOs for n‐type organic electronics. [ABSTRACT FROM AUTHOR]

The development of n‐type organic electrochemical transistors (OECTs) lags far behind their p‐type counterparts. In order to address this dilemma, we report here two new fused bithiophene imide dimer (f‐BTI2)‐based n‐type polymers with a branched methyl end‐capped glycol side chain, which exhibit good solubility, low‐lying LUMO energy levels, favorable polymer chain orientation, and efficient ion transport property, thus yielding a remarkable OECT electron mobility (μe) of up to ≈10−2 cm2 V−1 s−1 and volumetric capacitance (C*) as high as 443 F cm−3, simultaneously. As a result, the f‐BTI2TEG‐FT‐based OECTs deliver a record‐high maximum geometry‐normalized transconductance of 4.60 S cm−1 and a maximum μC* product of 15.2 F cm−1 V−1 s−1. The μC* figure of merit is more than one order of magnitude higher than that of the state‐of‐the‐art n‐type OECTs. The emergence of f‐BTI2TEG‐FT brings a new paradigm for developing high‐performance n‐type polymers for low‐power OECT applications. [ABSTRACT FROM AUTHOR]

High‐performance nonfullerene ternary organic solar cells (OSCs) with two polymer donors are less frequently reported because of the limited numbers of efficient polymer donors with good compatibility. Herein, a wide‐bandgap polymer P1 with a deep‐lying highest occupied molecular orbital (HOMO) level is incorporated as the third component into the benchmark PM6:Y6 binary system to fabricate ternary OSCs. The introduction of P1 not only leads to extended absorption coverage and forms a cascade‐like energy level alignment but also shows excellent compatibility with PM6, resulting in a favorable morphology in the ternary blend. More importantly, P1 possesses a deeper HOMO level (−5.6 eV) than most well‐known donor polymers, which enables resulting ternary OSCs with an improved open‐circuit voltage. As a result, the optimized ternary OSCs with 40 wt% P1 in donors achieve a power conversion efficiency (PCE) of 16.2% with a small nonradiative recombination loss of 0.23 eV, which is among the highest values of ternary OSCs based on two polymer donors. In addition, the ternary OSCs show a broad composition tolerance with a high PCE of over 14% throughout the whole blend ratios. These results provide an effective approach to fabricate efficient ternary OSCs by synergizing two wide‐bandgap polymer donors. [ABSTRACT FROM AUTHOR]

Multicolor emissive and responsive materials are highly attractive owing to their potential applications in various fields, and polymers are preferred for their good processability and high stability. Herein, we report a series of new polymers based on a methacrylate monomer containing a switchable boron chromophore. In spite of their unconjugated nature, interestingly, the homopolymers from this monomer display rare multicolor fluorescence in solution that is highly dependent on the degree of polymerization (DP). With an increasing DP, the local concentration of the chromophore increases, leading to a higher propensity for switching the blue‐emitting tricoordinate boron chromophore to the red‐emitting tetracoordinate one. The homopolymers also display temperature‐ and solvent‐dependent emission color change. Furthermore, pure white‐light emission could be achieved in various solvents by precisely tuning the homopolymer molecular weight, or in films/solid state by copolymerizing the emissive boron monomer with non‐emissive monomers in an appropriate ratio. [ABSTRACT FROM AUTHOR]

Dye-containing wastewater has caused serious environmental pollution. Herein, rationally designed spherical polyelectrolyte brushes (SPBs) with cationic charges, polystyrene-poly(2-aminoethylmethacrylate hydrochloride) (PS-PAEMH) as the absorbent, and compressed carbon dioxide as the antisolvent are proposed for the separation of the anionic dye eosin Y (EY) from a solution of mixed dyes. The adsorption behavior of EY onto PS-PAEMH was highly dependent on CO2 pressure, contact time, and initial concentration. The maximum adsorption capacity of PS-PAEMH was 335.20 mg g−1. FTIR and UV/Vis measurements proved that the electrostatic interactions between EY and PS-PAEMH played an important role in the absorbance process. The adsorption process fitted the pseudo-second-order kinetic model and Freundlich isotherm model very well. The combined dye and polymer brush could be easily separated through ion exchange by adding an aqueous solution of NaCl. Recovered PS-PAEMH retained a high adsorption capacity even after ten cycles of regeneration. This method provides a simple and effective way to separate ionic materials for environmental engineering. [ABSTRACT FROM AUTHOR]

A series of hybrid polyhydroxyurethane (PHU) materials were prepared from CO 2 , polypropylene glycol diglycidyl ether, amines, and bisphenol-A diglycidyl ether (BADGE). Firstly, the five-membered cyclocarbonate (5CC) as the CO 2 -sourced monomer was synthesized by a cycloaddition reaction from CO 2 and polypropylene glycol diglycidyl ether at 120 °C under 10 bar CO 2 pressure in the presence of an amberlyst catalyst. The selectivity of 5CC was confirmed through an analog computation method based on the results of 1 H NMR. Then, 5CC was reacted with excessive amines to produce the −NH 2 terminated pre-polymers. Finally, the pre-polymers reacted with BADGE to produce hybrid PHU materials. The effect of amine type and BADGE content on the properties of PHUs was studied by means of Fourier transform infrared spectra, dynamic mechanical thermal analysis, and thermogravimetric analysis and solvent swelling test. The results indicated that introducing BADGE as a chain extender not only enhances the gelation rate of PHU, but also improve the mechanical and thermal properties of PHU materials. [ABSTRACT FROM AUTHOR]

Carbonated soybean oil (CSBO) is a precursor of nonisocyanate polyurethanes (NIPUs). So far, the ruling catalysts for CSBO synthesis through the coupling of epoxidized soybean oil (ESBO) with CO2 are homogeneous ones. In this work, a heterogeneous catalyst, 5 wt % H3PW12O40 (PW)/ZrO2 was investigated for the coupling reaction and proved quite efficient. However, the catalyst showed poor reusability due to the difficult elimination of bulky by-products retained in the spent catalyst. To remedy this deficiency, the 5 wt % PW/ZrO2 was modified with 0.3% Pt. It is found that Pt addition markedly improved the reusability of the 5 wt % PW/ZrO2 without loss in carbonation activity. An ESBO conversion of 78.3% was obtained at the end of third recycle, indicating that Pt species incorporated could promote the removal of the by-products and hence protect the active centres of 5 wt %PW/ZrO2 catalyst. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 [ABSTRACT FROM AUTHOR]

The article presents research on waterborne polyurethane (WPU) adhesives modified by polystyrene (PS). In this study, proton nuclear magnetic resonance techniques were used to examine PS dispersions and (PU)-PS prepolymer. It was found that PS/polyester diol weight ratios improved several properties including thermal stability, mechanical properties and water resistance with regard to the performance of PU-PS adhesives.