Synthesis,two‐photon absorption,and optical power limiting of new linear and hyperbranched conjugated polyynes based on bithiazole and triphenylamine

Two new linear and hyperbranched conjugated polymers P1 and P2 have been synthesized by Sonogashira coupling reaction, in which the main chain consists of bithiazole moieties as electron acceptors and triphenylamino groups as donors. The conjugated polymers were characterized by TGA, UV–vis absorption, fluorescence emission, electrochemical cyclic voltammetry, and two‐photon absorption measurements. They exhibited excellent solubility in organic solvents and high thermal stability (5% of weight loss at 299 °C). The two‐photon absorption cross sections (σ) measured by the open aperture Z‐scan technique using 140 femtosecond (fs) pulse were determined to be 1014 and 552 GM per repeating unit for P1 and P2 , respectively. This result shows that the σ of linear conjugated P1 is higher than that of hyperbranched P2 , indicating that the linear polymer offers better intramolecular charge transfer ability. In THF, P1 and P2 exhibit intense frequency up‐converted fluorescence under the excitation of 140 fs pulses at 800 nm with the peaks located at 580 and 548 nm, respectively. Meanwhile, the optical limiting behaviors for the polymers were studied by using a focused 800 nm laser beam of 140 fs duration. It was found that these polymers also exhibit good optical‐limiting properties and make them potential candidates for optical limiters in the photonic fields. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Perylene diimide copolymers with dithienothiophene and dithienopyrrole: Use in n‐channel and ambipolar field‐effect transistors

Solution‐processable polymers consisting of perylene diimide (PDI) acceptor moieties alternating with dithienothiophene (DTT), N‐dodecyl‐dithienopyrrole (DTP), or oligomers of these donor groups have been synthesized. We have, in addition to varying the donor, varied the N,N′ substituents of the PDIs. The thermal, optical, electrochemical, and charge‐transport properties of the polymers have been investigated. The polymers show broad absorption extending from 300 to 1000 nm with optical band gaps as low as 1.2 eV; the band gap decreases with increasing the conjugation length of donor block, or by replacement of DTT by DTP. The electron affinities of the polymers, estimated from electrochemical data, range from ?3.87 to ?4.01 eV and are slightly affected by the specific choice of donor moiety, while the estimated ionization potentials (?5.31 to ?5.92 eV) are more sensitive to the choice of donor. Bottom‐gate top‐contact organic field‐effect transistors based on the polymers generally exhibit n‐channel behavior with electron mobilities as high as 1.7 × 10^–2 cm²/V/s and on/off ratios as high as 10⁶; one PDI‐DTP polymer is an ambipolar transport material with electron mobility of 4 × 10^–4 cm²/V/s and hole mobility of 4 × 10^–5 cm²/V/s in air. There is considerable variation in the charge transport properties of the polymers with the chemical structures. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

肝素钠掺杂球状聚吡咯的合成及其电化学电容

以生物制剂肝素钠为掺杂剂,由自组装方法合成出平均粒径为100 nm的球状聚吡咯(PPy),用作超级电容器电极材料.透射电镜(TEM)、循环伏安、恒流充放电和电化学交流阻抗测试表明,肝素钠掺杂聚吡咯呈现较好的形貌和电容性质,在电流密度3 mA/cm2下充放电,单电极比电容达到338 F/g.     

Soluble narrow band gap and blue propylenedioxythiophene-cyanovinylene polymers as multifunctional materials for photovoltaic and electrochromic applications

A family of soluble narrow band gap donor-acceptor conjugated polymers based on dioxythiophenes and cyanovinylenes is reported. The polymers were synthesized using Knoevenagel polycondensation or Yamamoto coupling polymerizations to yield polymers with molecular weights on the order of 10 000-20 000 g/mol, which possess solubility in common organic solvents. Thin film optical measurements revealed narrow band gaps of 1.5-1.8 eV, which gives the polymers a strong overlap of the solar spectrum. The energetic positions of the band edges were determined by cyclic voltammetry and differential pulse voltammetry and demonstrate that the polymers are both air stable and show a strong propensity for photoinduced charge transfer to fullerene acceptors. Such measurements also suggest that the polymers can be both p- and n-type doped, which is supported by spectroelectrochemical results. These polymers have been investigated as electron donors in photovoltaic devices in combination with PCBM ([6,6]-phenyl C(61)-butyric acid methyl ester) as an electron acceptor based on the near ideal band structures designed into the polymers. Efficiencies as high as 0.2% (AM1.5) with short circuit current densities as high as 1.2-1.3 mA/cm(2) have been observed in polymer/PCBM (1:4 by weight) devices and external quantum efficiencies of more than 10% have been observed at wavelengths longer than 600 nm. The electrochromic properties of the narrow band gap polymers are also of interest as the polymers show three accessible color states changing from an absorptive blue or purple in the neutral state to a transmissive sky-blue or gray in the oxidized and reduced forms. The wide electrochemical range of electrochromic activity coupled with the strong observed changes in transmissivity between oxidation states makes these materials potentially interesting for application to electrochromic displays.     

Triazatruxene-containing hyperbranched polymers: Microwave-assisted synthesis and optoelectronic properties

Hyperbranched polymer structures represent a class of high-functionality building blocks with excellent three-dimensional topology for the construction of highly substituted conjugated polymers. In this contribution, an efficient microwave synthesis protocol toward the synthesis of conjugated hyperbranched polymers is presented. A novel series of soluble hyperbranched polyfluorenes (PTF1-PTF3) incorporating triazatruxene moiety as the branch units with various branching degrees have thus been successfully constructed with good yields and high molecular weight via a facile “A2+B2+C3” approach. The structures of the hyperbranched polymers were confirmed by NMR and GPC. Their thermal, optical, and electrochemical properties of the hyperbranched polymers were also investigated. The results showed that introduction of triazatruxene units into the hyperbranched structure endowed the polymer with good thermal stability and highly amorphous properties. Photophysical investigation of PTFx revealed strong blue emission in both solution and solid states. Hyperbranched polymers with higher degree of branching and proper content of linear fluorene units exhibited better photophysical properties in terms of narrow emission spectra and relatively high quantum efficiency as well as improved thermal spectral stability. The triazatruxene branching unit also played a role in raising the HOMO energy levels relative to those of polyfluorenes that would help to improve the charge injection and transport properties. The incorporation of triazatruxene unit into hyperbranched polymers has thus explored an effective avenue for constructing optoelectronic polymers with improved functional characteristics.     

Synthesis,Structural Characterization,and Electrochemical Properties of Isotruxene–Polyaniline Hybrid Systems

The synthesis, structural characterization, and electrochemical properties of a series of isotruxene–polyaniline (PANI ) hybrid systems (SITPs , SITAs , and CITs ) are reported. The syntheses were performed by in situ chemical oxidative polymerization of aniline in the presence of isotruxene additives ITP and/or ITA at specific aniline‐to‐additive molar ratios. The polymers SITPs and SITAs display granular morphology, but for the polymers CITs a spherical morphology with a diameter of 300–500 nm is found. These hybrid systems display electrochemical capacitive performance superior to those of the parent PANI prepared under the same condition (e.g., 385–463 vs. 181 F/g at 3 mA /cm² current density during charge–discharge test). Molecular (star‐shaped or hyperbranched vs. linear topology) and supramolecular (isotruxene–PANI π–π and cation–π interactions) models in accounting for the observed morphology and electrochemical properties are provided.     

Electrical properties of electrochemically doped organic semiconductors using light-emitting electrochemical cells

We present a study of the electrical properties of electrochemically doped conjugated polymers using polymeric light-emitting electrochemical cells (PLECs) and interpreting the results according to a phenomenological model (PM) which assumes that, above the device turn-on voltage, the bulk transport properties of the doped organic semiconductor are responsible for the main contribution to the whole device conductivity. To confirm the predictions of this model, the dependence of the conductivity of PLECs with different parameters is evaluated and compared with the behavior expected for a doped semiconducting polymeric material. The organic semiconductor doping level, the blend concentration of organic semiconducting molecules, the device thickness, the charge carrier mobility, and the temperature are the parameters varied to perform this analysis. We observed that the device conductivity is independent of the active layer thickness, weakly dependent on the temperature, but strongly dependent on the semiconductor doping level, on the semiconductor fraction in the blend, and on the intrinsic charge carrier mobility. These results were well described by the variable range hopping (VRH) model, which has been widely employed to describe the charge transport in doped semiconducting polymeric materials, confirming the prediction of the phenomenological model. The current analysis demonstrates that PLECs are a suitable system for studying, in situ, the electrochemical doping of semiconducting polymers, permitting the evaluation of material properties as, for instance, the density of electronic charge carriers (and, consequently, the ionic charge carrier concentration) necessary to achieve the maximum electrochemical doping level of the organic semiconductor.     

Microscopy and spectroscopy of interactions between metallopolymers and carbon nanotubes

The interaction between redox polymers, based on Ru- or Os-bis(2,2'-bipyridyl)-poly(4-vinylpyridine), and carbon nanotubes was investigated by spectroscopic and microscopic techniques. These metallopolymers were found to be excellent dispersants for nanotubes, as a result of a good wetting interaction between polymer and nanotubes. The results obtained show that well-coated individual nanotubes can be obtained. In addition, interactions between nanotubes and polymers did not significantly affect the electronic and electrochemical properties of the metallopolymers. On the basis of the electrochemical properties of the polymers this opens the possibility of adding functionality through interaction with nanotubes, either as redox active materials with enhanced mechanical properties or by using these modified nanotubes as nanosized electrochemical sensors.     

Electrochemical sensors and biosensors based on redox polymer/carbon nanotube modified electrodes: A review

The aim of this review is to present the contributions to the development of electrochemical sensors and biosensors based on polyphenazine or polytriphenylmethane redox polymers together with carbon nanotubes (CNT) during recent years. Phenazine polymers have been widely used in analytical applications due to their inherent charge transport properties and electrocatalytic effects. At the same time, since the first report on a CNT-based sensor, their application in the electroanalytical chemistry field has demonstrated that the unique structure and properties of CNT are ideal for the design of electrochemical (bio)sensors. We describe here that the specific combination of phenazine/triphenylmethane polymers with CNT leads to an improved performance of the resulting sensing devices, because of their complementary electrical, electrochemical and mechanical properties, and also due to synergistic effects. The preparation of polymer/CNT modified electrodes will be presented together with their electrochemical and surface characterization, with emphasis on the contribution of each component on the overall properties of the modified electrodes. Their importance in analytical chemistry is demonstrated by the numerous applications based on polymer/CNT-driven electrocatalytic effects, and their analytical performance as (bio) sensors is discussed.     

Size and surface effects of prussian blue nanoparticles protected by organic polymers

Prussian blue (PB) nanoparticles protected by organic polymers such as poly(vinylpyrrolidone) (PVP) and poly(diallyldimethylammonium chloride) (PDDA) were prepared. Different experimental conditions (concentrations of Fe ions and feed ratios of Fe to the polymers) have been investigated to control the size of the PB nanoparticles. For example, the averaged dimensions of the PB nanoparticles were tuned from 12 to 27 nm by use of PVP in the different conditions. Addition of PDDA produced the PB nanoparticles with very small dimensions (5-8 nm) by an effective electrostatic interaction. We found that the surface environments of the PB nanoparticles affect the inherent properties of PB. The shifts of charge transfer (CT) absorptions from Fe(2+) to Fe(3+) in the PB nanoparticles resulted from the surface-protecting polymers. Especially, the PB nanoparticles with the PVP protection show high solubility in a variety of organic solvents and a solvent-dependent CT absorption. Measurement of the magnetic properties of the PB nanoparticles showed unprecedented size-dependency, surface effect, and superparamagnetic properties.     

Energy level tuning of polythiophene derivative by click chemistry‐type postfunctionalization of side‐chain alkynes

A polythiophene derivative substituted with electron‐rich alkynes as a side chain was synthesized using the Suzuki polycondensation reaction. The electron‐rich alkynes underwent the “click chemistry”‐type quantitative addition reaction with strong acceptor molecules, such as tetracyanoethylene (TCNE) and 7,7,8,8‐tetracyanoquinodimethane (TCNQ), resulting in the formation of donor–acceptor chromophores. All polymers showed excellent solubilities in the common organic solvents as well as good thermal stabilities with their 5% decomposition temperatures exceeding 230 °C. The TCNE‐/TCNQ‐adducted polymers displayed well‐defined charge‐transfer (CT) bands in the low energy region. The CT energy of the TCNE‐adducted polymer was 2.56 eV (484 nm), which was much greater than that of the TCNQ‐adducted polymer [1.65 eV (750 nm)]. This result was supported by the electrochemical measurements. The electrochemical band gaps of the TCNE‐adducted polymers were much greater than those of the corresponding TCNQ‐adducted polymers. Furthermore, the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels, determined from the first oxidation and first reduction peak potentials, respectively, decreased with the increasing acceptor addition amount. All these results suggested that the energy levels of the polythiophene derivative can be tuned by varying the species and amount of the acceptor molecules using this postfunctionalization method. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Synthesis and photophysical properties of hyperbranched polyfluorenes containing 2,4,6-tris(thiophen-2-yl)-1,3,5-triazine as the core

A series of new hyperbranched polymers containing a 2,4,6-tris(thiophen-2-yl)-1,3,5-triazine core unit and polyfluorene chain arms have been synthesized via Suzuki coupling, and characterized by NMR, IR and GPC. All the polymers exhibit good thermal stability with a high decomposition temperature. By changing the 2,4,6-tris(thiophen-2-yl)-1,3,5-triazine/fluorene ratio the UV-vis absorption and emission spectra can be partially tuned. It has been found that the polymers containing a low ratio of 2,4,6-tris(thiophen-2-yl)-1,3,5-triazine units (P1-P3) have an absorption maximum around 385 nm, localized in the polyfluorene chain, and a shoulder around 425 nm ascribable to a charge transfer state involving the fluorene and the 2,4,6-tris(thiophen-2-yl)-1,3,5-triazine core. Increasing the molar ratio of the 2,4,6-tris(thiophen-2-yl)-1,3,5-triazine unit enhances the charge transfer band which becomes dominant for P4. The LUMO level of these polymers is relatively low due to the electron affinity of the triazine group. The polymers show dual emission, with a structured band in the blue (410-440 nm), attributed to the polyfluorene, and a broad band in the red (470-500 nm) associated with the charge transfer state. All the polymers exhibit two-photon absorption activity in the range of 660 to 900 nm with the maximum two-photon absorption (TPA) cross-section red-shifted from the corresponding linear absorption. The values of the TPA cross-sections vary from 1000 to 5000 GM, following the 2,4,6-tris(thiophen-2-yl)-1,3,5-triazine/fluorene ratio.     

Synthesis and characterization of novel low band-gap polymers containing squaraine units

Novel conjugated polymers based on squaric acid having 2,5-Bis[(E)-N-alkylpyrrol-2-ylvinyl]-3-alkylthiophene(PVTVP) unit in the main chain were successfully synthesized in good yields through polycondensation reaction.Their molecular structures were characterized by FT-IR and ~1H NMR.They have good solubility in common organic solvents,good thermal stability by thermal gravimetric analysis and high molecular weights.Their optical properties were investigated by UV-vis absorption spectra in CH_2Cl_2 solution,the results indicated all these compounds showed broad and strong spectral responses from 200nm to 900nm, suggesting their potential for application as organic plastic solar cells.     

含Ullazine结构基元的共轭聚合物的合成及其光电性能研究

将Ullazine结构基元引入到聚合物主链或侧链中,分别与吡咯并吡咯二酮(DPP)、2,5-双(三甲基锡)噻吩共聚得到了二元共聚物PB和三元共聚物PT,分别利用凝胶渗透色谱和热重分析表征了聚合物的分子量和热稳定性,并研究了聚合物的光物理、电化学和光伏性能.基于共聚物PB和PT作为电子给体材料的聚合物太阳能电池器件测试结果表明,二元共聚物PB由于具有较低的能级水平从而获得较高开路电压,而侧链含Ullazine结构基元的三元共聚物PT具有更宽的吸收光谱和更高的空穴迁移率,获得了更高的短路电流和能量转换效率.     

Synthesis and characterization of novel ferrocenyl glycidyl ether polymer,ferrocenyl poly (epichlorohydrin) and ferrocenyl poly (glycidyl azide)

Poly (ferrocenyl glycidyl ether) was synthesized by polymerization of 2-[(4-ferrocenylbutoxy)methyl]oxirane (FcEpo) using toluene solution of methylaluminoxane as the catalyst. Copolymerization of 2-[(4-ferrocenylbutoxy)methyl]oxirane with epichlorohydrin was used for the synthesis of another ferrocenyl based poly (epichlorohydrin). Ferrocenyl based poly (glycidyl azide), GAP, was synthesized by treatment of sodium azide with this copolymer in DMF as solvent at room temperature. The synthesized ferrocenyl based polymers were characterized by FT-IR, ¹HNMR, UV–Vis, TGA, DSC and GPC analysis. The UV–Vis spectra of synthesized polymers show the absorption band of ferrocene moiety at about 450 nm. The TGA and DSC analysis show that poly (ferrocenyl glycidyl ether) has good thermal stability. The TGA analysis shows that the copolymerization of 2-[(4-ferrocenylbutoxy)methyl]oxirane with epichlorohydrin improved the thermal stability of the copolymer. The GPC analysis of poly (ferrocenyl glycidyl ether), ferrocenyl based poly (epichlorohydrin) and Ferrocenyl based poly (glycidyl azide) show the PDI between 1.14–1.17. The electrochemical behavior of synthesized polymers was investigated by cyclic voltammetry (CV) measurements. The CV curves of synthesized polymers show good electrochemical performance and there is one redox system with the single-electron reversible reaction that associated with ferrocene moiety in polymers structure. The anodic and cathodic peak currents increased with scan rate confirmed redox reactions in the system are kinetically fast diffusion-controlled reactions.     

Low bandgap π‐conjugated copolymers based on fused thiophenes and benzothiadiazole: Synthesis and structure‐property relationship study

A series of low bandgap conjugated polymers consisting of benzothiadiazole alternating with dithienothiophene (DTT) or dithienopyrrole (DTP) unit with or without 3‐alkylthiophene bridge have been synthesized. Effect of the fused rings and 3‐alkylthiophene bridge on the thermal, optical, electrochemical, charge transport, and photovoltaic properties of these polymers have been investigated. These polymers show broad absorption extending from 300 to 1000 nm with optical bandgaps as low as 1.2 eV; the details of which can be varied either by incorporating 3‐alkylthiophene bridge or by replacing DTT with DTP. The LUMO levels (?2.9 to ?3.3 eV) are essentially unaffected by the specific choice of donor moiety, whereas the HOMO levels (?4.6 to ?5.6 eV) are more sensitive to the choice of donor. The DTT and DTP polymers with 3‐alkylthiophene bridge were found to exhibit hole mobilities of 8 × 10^?5 and 3 × 10^?2 cm² V^?1 s^?1, respectively, in top‐contact organic field‐effect transistors. Power conversion efficiencies in the range 0.17–0.43% were obtained under simulated AM 1.5, 100 mW cm^?2 irradiation for polymer solar cells using the DTT and DTP‐based polymers with 3‐alkylthiophene bridge as donor and fullerene derivatives as acceptor. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5498–5508, 2009     

丙烯酸接枝邻苯二酚衍生物的二次聚合

合成了2种聚合前驱体邻苯二丙烯酸酯(o-PDA)和2-甲氧基苯丙烯酸酯(2-MOPA), 分别通过与丙烯酸(AA)自由基共聚得到邻苯二丙烯酸酯-丙烯酸共聚物(O1)和2-甲氧基苯丙烯酸酯-丙烯酸共聚物(O2). 产物邻苯二酚(o-DHB)-O1(质量比1∶1)和1-羟基-2-甲氧基苯(HMOB)-O2(质量比1∶1)分别在乙腈/二氯甲烷-三氟化硼乙醚体系中直接阳极氧化聚合获得交联网状共聚物P1和P2. P1和P2均可溶于DMSO, 而难溶于ACN, DCM和THF等有机溶剂. 通过UV-Vis, FTIR和 ¹H NMR对交联共聚物膜的结构进行了表征. AA的引入不仅可以增加链的柔韧性, 而且提高了共聚物的力学性能. 而o-DHB/ HMOB的引入极大地减弱了单体的聚合位阻, 实现了单体的二次聚合, 同时也增强了单体及聚合物的电化学活性. 荧光光谱显示, 得到的2种交联共聚物膜分别在415和487 nm处有较强的发射峰, 表明共聚物仍具有良好的蓝色发光性能, 且聚丙烯酸结构的引入并没有对聚邻苯二酚(Po-DHB)和聚(1-羟基-2-甲氧基苯)(PHMOB)产生较大的荧光猝灭作用. 热重分析曲线(TGA)表明2种交联共聚物膜均具有较高的热稳定性.     

导电高分子的最近进展

因为导电高分子结合了金属与塑料的优点,他们一直受到很大的关注。但是他们的应用受到一些因素的影响,包括他们的电学性质,稳定性和可加工性。近来,导电高分子的性能得到很大的提高。他们在许多领域的重要应用被论证,比如透明电极,可拉伸电极,神经界面,热电转换和能量储存。这篇文章简单综述了导电高分子的电导提高和它们在热电转换,超级电容器和电池的应用。     

Zn(II)-containing metallo-supramolecular polymers: synthesis,photophysical and electrochemical properties

Abstract

Two novel building blocks M1, M2 with different electronic structures, were synthesized based on 2,2′:6′,2″-terpyridine modified with cyano-p-phenylenevinylene (CN-PV) and carbazole moieties through Knoevenagel condensation and Suzuki coupling, respectively. Directed by transition metal ion Zn²⁺, the metallo-homopolymers P1, P2 and metallo-copolymer P3 were obtained via self-assembly polymerization. The structures of the monomers and metallo-supramolecular polymers were fully characterized by MS, ¹H-NMR and ¹³C-NMR. Meanwhile, the UV–vis absorption, photoluminescence (PL) and electrochemical properties of these compounds were systematically investigated. With respect to that of the monomers, both the UV–vis absorption and PL spectra of the polymers are significantly red-shifted. The resulting metallo-supramolecular polymers show similar double absorption peaks (342, 418?nm for P1, 339, 410?nm for P2, and 332, 412?nm for P3), which is caused by the π–π* transition and intramolecular charge transfer (ICT). Further, all the polymers display red-orange emission in toluene and narrow electrochemical energy gaps of 1.46, 1.65 and 1.48?eV for P1, P2, and P3, respectively.