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1.
π-Conjugated polymers bearing nitro substituent(s), e.g., poly(aryleneethynylene) (PAE) type polymers and poly(4,8-dinitroanthraquinone-1,5-diyl) P(4,8-NO2-1,5-AQ), show semiconducting properties with electrical conductivities of an order of 10−7 to 10−6 S · cm−1 at room temperature without special oxidation and reduction of the polymer. P(4,8-NO2-1,5-AQ) shows a large shift of phase in alternating current (ac) measurements and a unique magnetism at low temperature.  相似文献   

2.
A new series of donor-acceptor (D-A)-type semiconductive polymers were generated by the integration of electron-deficient alkyl chain anchored triazole (TA) moieties and electron-rich pyrene units into the polymer skeleton. The polymer series demonstrated satisfactory light-harvesting ability and suitable band gaps. In the series, polymer P-TAME benefits from a minimized exciton binding energy, strongest D-A interaction, and favorable hydrophilicity, affording an outstanding photocatalytic H2 evolution rate of ca. 100 μmol h−1 (10 mg polymer, AQY420 nm=8.9 %) and H2O2 production rate of ca. 190 μmol h−1 (20 mg polymer) under visible-light irradiation, which is superior to most currently reported polymers. All polymers in the series can mediate water oxidation reactions to evolve O2. Thus, these TA-based polymers open up a new avenue toward tailor-made efficient photocatalysts with broad photocatalytic activities.  相似文献   

3.
Developing new D-A conjugated polymer system for thermoelectric (TE) application is highly desirable. Herein, a series of random copolymers by incorporating 3,4-ethylenedioxythiophene (EDOT) electron rich units into a diketopyrrolopyrrole (DPP) D-A conjugated polymer were designed and synthesized. Compared to the alternating conjugated copolymer PDPP-3T, the HOMO level of the random copolymers are increased as part of the electron deficiency acceptor DPP units in the polymer chain were superseded by electron rich EDOT, which could contribute to effective p-doping. Moreover, through incorporating EDOT to construct random copolymers, it can also induce an orientation change from face-on dominated to edge-on dominated orientation as well as enhance the packing of copolymer chains, which is beneficial to the charge transport. Under same doping condition, the electrical conductivities of the doped polymers increase and the Seebeck coefficient decrease as the increasing of EDOT content, resulting in an optimized power factor of 6.4 μW m−1 K−2 for the random polymer with EDOT content of 40% which is four times higher than that of alternating conjugated copolymer PDPP-3T. These results demonstrated that constructing random copolymers by incorporating more electronic donors into D-A conjugated polymers may be a promising strategy for developing TE conjugated polymers.  相似文献   

4.
Efficient and scalable production of high-quality and processable two-dimensional (2D) polymers are highly desired but have not yet been reported. Herein, we demonstrate a convenient noncovalent functionalization strategy for producing highly uniform, aqueous processable and semiconducting 2D triazine polymers. Experimental and theoretical analysis reveal that the aromatic amphiphilic 1-pyrenebutyrate can adsorb and intercalate into the interlayer of bulk crystalline covalent triazine framework (CTF) through noncovalent π-π stacking interaction between the pyrene moiety and the porous basal plane of 2D triazine polymer layer, which greatly facilitate the exfoliation of CTF in water in large scale. The as-prepared highly water-dispersible single-layer/few-layer 2D triazine polymer nanosheets can be easily processed into ultralight aerogels with a density of 5–15 mg cm−3, which can be further shaped into mechanically strong films upon simple compression. This noncovalent functionalization not only improve the dispersibility and processability of 2D triazine polymer, but also optimize its band structure and promote the photogenerated carrier separation via an interesting surface molecule doping effect, thus resulting in a remarkable photocatalytic hydrogen evolution rate of 1249 μmol h−1 (24980 μmol g−1 h−1) and apparent quantum efficiency up to 27.2 % at 420 nm for the 2D triazine polymer, outperforming most metal-free photocatalysts ever reported.  相似文献   

5.
Degradation of Coordination Polymers to the Monomer and Competition of Polymerization and Chemical Scissors on Carbazolates of Yb and Eu with N‐Phenylpiperazine The coordination polymers , Ln = Yb, Eu, Cbz = carbazolate anion, C12H8N, can be degraded by the use of strong N‐donor ligands like N‐phenylpiperazine (Phpip = (C6H5)C4H8NNH) as chemical scissors. The degradation process for the ytterbium containing polymer ends in the monomeric compound [Yb(Cbz)3(Phpip)2]·1/2Phpip and includes an oxidation step YbII → YbIII. Thus the circle of reactions of Yb metal with carbazole (CbzH) starting in liquid NH3 to the coordination polymer and ending with its degradation by the use of chemical scissors is resolved. Transformation on europium has been started on the base of both metals leading to coordination polymers of the same chemical formula. However already the prelude of reactions differs for Eu as the electride induced reaction of Eu metal with CbzH in liquid ammonia followed by Phpip treatment gives single crystalline [Eu2(Cbz)4(NH3)2(Phpip)4]·2Phpip. This dimeric molecule contains EuII and ligands of all reaction steps, NH3, Cbz, Phpip, and is thereby an interesting starting point for the resolution of polymer formation and degradation as well as a competition of these counter reactions.  相似文献   

6.
Radical cyclopolymerization of 3-phenyl[5]ferrocenophane-1,5-dimethylene ( 2 ) and copolymerization with styrene gave polymers ( 3 and 4 ) with [3]ferrocenophane moieties pendant to the backbone. Cyclic voltammetry (CV) on polymer 3 in CH2Cl2 showed two oxidation waves at −0.13 and +0.05 V (versus ferrocene/ferrocenium) and CV on copolymer 4 showed one oxidation potential at −0.03 V. CV on 3 in dimethylacetamide showed only one oxidation potential at −0.10 V. Near-IR spectroscopy of partially oxidized 3 showed a broad intervalence band at ca. 2000 nm, indicative of low-energy barriers to electron hopping. Conductivity measurements on 3 and poly(vinylferrocene) (PVFc) oxidatively doped with iodine vapors under an argon atmosphere showed a maximum conductivity ca. 5 × 10−5 S/cm before the samples cracked, while 4 exhibited a maximum conductivity of 1.6 × 10−6 S/cm. On iodine doping under ambient conditions, polymers 3 , 4 , and PVFc showed maximum conductivities of 7.6 × 10−4, 9.5 × 10−5, and 5.5 × 10−5 S/cm, respectively. Conductivity measurement were also performed on samples of 3 +BF4 with oxidation levels ranging from 8 to 56%. Conductivities of these samples ranged from ca. 10−10 to 10−9 S/cm under vacuum and ca. 10−6 S/cm under ambient conditions, indicating that atmospheric moisture has a strong effect on the conductivity. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 3365–3376, 1997  相似文献   

7.
Dimensionality plays an important role in the charge transport properties of organic semiconductors. Although three-dimensional semiconductors, such as Si, are common in inorganic materials, imparting electrical conductivity to covalent three-dimensional organic polymers is challenging. Now, the synthesis of a three-dimensional π-conjugated porous organic polymer (3D p-POP) using catalyst-free Diels–Alder cycloaddition polymerization followed by acid-promoted aromatization is presented. With a surface area of 801 m2 g−1, full conjugation throughout the carbon backbone, and an electrical conductivity of 6(2)×10−4 S cm−1 upon treatment with I2 vapor, the 3D p-POP is the first member of a new class of permanently porous 3D organic semiconductors.  相似文献   

8.
The formation of carbonaceous clusters in ion‐irradiated polymer films was investigated extensively. Information about these clusters may be obtained with ultraviolet–visible (UV–vis) spectroscopy. The optical band gap (Eg), calculated from the absorption edge of the UV spectra of these polymers, can be correlated to the number of carbon atoms (N) in a cluster with the modified Tauc equation. The structure of the cluster is also related to Eg; for example, a six‐membered‐benzene‐ring‐type structure has an Eg of ≈5.3 eV, whereas a buckminsterfullerene‐type structure has an Eg of ≈4.9 eV. These clusters are responsible for the electrical conductivity in these films. In this work, polycarbonate films (20 μm thick) were irradiated with 45‐MeV Li ions at fluences of 1 × 1012 to 1 × 1013 cm−2 and were characterized with UV–vis spectroscopy and impedance measurements. The Eg values, calculated from the absorption edge in the 280–315‐nm region with the Tauc relation, varied from 4.39 to 4.35 eV for the pristine and various irradiated samples, respectively. The cluster size showed a range of 60–62 carbon atoms per cluster. The sheet conductivity (σdc) and loss (tan δ) values of 10−16 Ω−1cm−1 and 10−3 for the pristine sample changed to 10−15 Ω−1cm−1 and 10−2, respectively, for the irradiated samples. This increase in the values of σdc and tan δ may be correlated to the increase in the size of the carbonaceous clusters. This study provides insight into the mechanism of electrical conductivity in irradiated polymers. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 1589–1594, 2000  相似文献   

9.
A series of poly(arylene ether)s containing triphenylmethane moiety were synthesized by the nucleophilic displacement of aromatic dihalides with bisphenols in an aprotic solvent in the presence of excess potassium carbonate. High molecular weight and fibrous polymers in white color can be readily afforded in short reaction time. The structures of the synthesized monomers and polymers were investigated by 1H NMR and MS techniques. The sulfonation position of the synthesized polymer can be easily controlled and the water-up-take can be conveniently tailored by changing the amount of sulfonation agent. This sulfonated polymer 4b is soluble in polar organic solvents, such as NMP, DMAc, DMSO, DMF, ethylene glycol monomethyl ether, and can be readily cast into tough and smooth films from solutions. The sulfonated polymers can be potentially used as the proton-exchange membranes for fuel-cells.  相似文献   

10.
Two new bithiophene imide (BTI)‐based n‐type polymers were synthesized. f‐BTI2‐FT based on a fused BTI dimer showed a smaller band gap, a lower LUMO, and higher crystallinity than s‐BTI2‐FT containing a BTI dimer connected through a single bond. s‐BTI2‐FT exhibited a remarkable electron mobility of 0.82 cm2 V−1 s−1, and f‐BTI2‐FT showed a further improved mobility of 1.13 cm2 V−1 s−1 in transistors. When blended with the polymer donor PTB7‐Th, f‐BTI2‐FT‐based all‐polymer solar cells (all‐PSCs) attained a PCE of 6.85 %, the highest value for an all‐PSC not based on naphthalene (or perylene) diimide polymer acceptors. However, s‐BTI2‐FT all‐PSCs showed nearly no photovoltaic effect. The results demonstrate that f‐BTI2‐FT is one of most promising n‐type polymers and that ring fusion offers an effective approach for designing polymers with improved electrical properties.  相似文献   

11.
Pyrrole, thiophene, and a mixture of the two monomers were electrochemically polymerized to investigate polymerization rates and the morphology change of the polymer matrix, and to improve the aging and cyclic voltammetric behaviors of the polymers. Thiophene was polymerized on a smooth surface of Pt electrode by two steps. The first step was controlled by electron transfer at the electrical double layer and the other by diffusion of the monomer reacting on the immobilized layer consisting of the precoated thiophene polymer. The electropolymerization rate of the second step was 1.85 × 10−4 cm3 mol−1 s−1, which is faster by 8.63 × 102 times than the first step. Some supporting electrolytes such as KPF6, LiClO4, TBAP, and TBABF4 were employed in the polymerization reaction to see the effects of dopant anions on the polymerization rate, and KPF6 was the fastest one at 2.41 × 10−6 cm s−1. However, owing to its sensitivity to oxygen, LiClO4 was used for the polymerization that is fairly stable in air and the same rate as KPF6. For the competitive polymerization reaction of the two monomers the rate of thiophene was found to be about 11 times slower than that of thiophene alone. When the starting concentration of the thiophene monomer was higher than pyrrole by five times, its portion in the composite polymer was found to be only 8–10%. However, this level gave desirable results in terms of redox properties and aging. The resistance against aging was explained by the morphology change, which came from great shrinking of its porosity. © 1997 John Wiley & Sons, Inc.  相似文献   

12.
Typical n-type conjugated polymers are based on fused-ring electron-accepting building blocks. Herein, we report a non-fused-ring strategy to design n-type conjugated polymers, i.e. introducing electron-withdrawing imide or cyano groups to each thiophene unit of a non-fused-ring polythiophene backbone. The resulting polymer, n-PT1 , shows low LUMO/HOMO energy levels of −3.91 eV/−6.22 eV, high electron mobility of 0.39 cm2 V−1 s−1 and high crystallinity in thin film. After n-doping, n-PT1 exhibits excellent thermoelectric performance with an electrical conductivity of 61.2 S cm−1 and a power factor (PF) of 141.7 μW m−1 K−2. This PF is the highest value reported so far for n-type conjugated polymers and this is the first time for polythiophene derivatives to be used in n-type organic thermoelectrics. The excellent thermoelectric performance of n-PT1 is due to its superior tolerance to doping. This work indicates that polythiophene derivatives without fused rings are low-cost and high-performance n-type conjugated polymers.  相似文献   

13.
Double‐layer electroluminescent (EL) devices composed of an alternating polymer with mono‐, di‐, or tri‐silanylene and phenylene units, [(Si R) m (C6H4)] n (R = alkyl, m = 1–3) as a hole‐transporting layer, and tris(8‐quinolinolato)­aluminium(III) complex (Alq) as an electron‐transporting–emitting layer were fabricated. The longer silanylene chain lengths in the polymer, on going from m = 1 to m = 2 and 3, result in better electrical properties for the EL devices, implying that the σ–π conjugation in the polymers plays an important role in the hole‐transporting properties, including the hole‐injection efficiency from an anode. This is in marked contrast to the improved hole‐transporting properties that occur in response to reducing the silanylene chain length of silanylene‐diethynylanthracene polymers previously reported. The UV absorption maxima of silanylene‐phenylene polymers shift to longer wavelengths with increasing m, and their oxidation peak potentials in cyclic voltammograms shift to lower potential with increasing m, in accordance with the improved electrical properties of the device that are observed with the polymers containing the longer silanylene chain. A triple‐layer EL device with a hole‐transporting layer of monosilanylene‐diethynylanthracene polymer, an electron‐transporting–emitting layer of Alq, and an electron‐blocking layer of N,N′‐diphenyl‐N,N′‐bis(3‐methylphenyl)‐1,1′‐biphenyl‐4,4′‐diamine (TPD) exhibited a maximum efficiency of 1.0 lm W−1 and a maximum luminance of 14750 cd m−2, both of which are much higher than the values obtained from a conventional EL device with TPD/Alq. Copyright © 1999 John Wiley & Sons, Ltd.  相似文献   

14.
The effect of substrates on the addition polymerization of 1,4-benzenedithiol (BDT) to 1,4-diethynylbenzene (DEB) in the solid state and the electronic properties of the polymers obtained were studied. As the substrate polymer sheets, for instance, PET (poly (ethylene terephthalate)) sheet, ON-6 (oriented nylon-6) sheet and so on having surface free energies Γs from 27.4 to 55.0 erg/cm2 were used. At the monomer sublimation temperature of 60°C, the S wt% (sulfur content) and the cis content of the polymers were not affected by the kind of polymer sheets. However, the molecular weights, M¯n of the polymers polymerized on the polymer sheets were 13,000–30,000, and the values were several times higher than the molecular weight of the polymers polymerized on glass plate. On the other hand, at the sublimation temperature of 82°C, the cis content of the polymers apparently increased with decreasing d-value of the polymer sheets. On X-ray diffraction patterns of monomer mixtures sublimed onto polymer sheets, the diffraction intensities and the diffraction peak positions were concerned with the d-value of the polymer sheets. Using polymer sheets, the diffraction peak intensities of the monomer mixture at 7.73 and 7.58 Å decreased compared with those on glass plate. In contrast, the peak at 3.65 Å, which is a negligibly small peak on glass plate, obviously increased. However, as the d-value of the polymer sheets (PET 3.45 Å; OPP (oriented polypropylene) 5.2 Å) increased, the diffraction peak intensities at 7.73 Å and 7.58 Å gradually increased and the diffraction peak intensity at 3.65 Å gradually decreased. The parallel electrical conductivities (σ||) toward the layered structural polymer on PET, ON-6 and glass plate under air atmosphere were 10−7, 10−9 and 10−11 S/cm, respectively. Under a reduced pressure of 10−3 mmHg, the σ|| values of each polymer lowered by one or two orders of magnitude. On the other hand, the σ|| values of the nonlayered structural polymers under air atmosphere were about 10−11–10−12 S/cm and were independent of the substrates. Even under a reduced pressure of 10−3 mmHg, the σ|| values hardly changed and remained at 10−11–10−12 S/cm. The vertical electrical conductivities (σ) of the layered structural polymers on conductive PET sheet coated by indium tin oxide or NESA glass plates were independent of the substrates and were 10−14 S/cm under air atmosphere. The σ values of the nonlayered structural polymers also exhibited the same values. The reversible change of the amount of the layered structural polymer on PET sheet was also caused by irradiation of the photo-light which is the effective wavelength for the phase transition of the polymers mounted on glass plate. The σ|| value of the layered structural polymer on ON-6 sheet reversibly changed with the amount of the layer structure controlled by the photo-light, that is, the σ|| increased up to about one order of magnitude by the photo-light at 545.6 nm. On the other hand, the || decreased to about one order of magnitude by the photo-light at 539.6 nm. Anisotropic conductivity with respect to σ|| and σ, and oxygen doping mechanisms were discussed in relation to the layer structure of polymers. © 1997 John Wiley & Sons, Ltd.  相似文献   

15.
Sulfonated polyethersulfone Cardo was prepared by solvent-free reaction of concentrated sulfuric acid on the polymer. The polymer can be sulfonated to different degrees by control of the reaction temperature and time. The degradation of it main chain was shown to occur at high reaction temperature or at very long time. Higher sulfonation obtained at longer reaction times led to soluble polyelectrolytes. Polymers with an ion exchange capacity lower than 1.75 equiv. kg−1 are not soluble in water while being hydrophilic. Asymmetric membranes can be prepared from the latter polymers by the wet phase-inversion method with water as the precipitation medium. They can be used as hydrophilic membranes for ultrafiltration or nanofiltration.  相似文献   

16.
The chemical synthesis of new electroconducting poly(2,5-thienylene)s containing alkylhydroxy and alkylester side-chains in the β-position of the thiophene rings is reported. The polymers were obtained by oxidative homopolymerization or copolymerization of 2-(3-thienyl)ethanol and 2-(3-thienyl)ethyl hexanoate by FeCl3 in nitromethane. Structural characterization using elemental analysis, FT-IR and NMR spectroscopy shows that a partial nucleophilic substitution of the hydroxy group by chlorine and a partial cleavage of the ester function take place during polymerization. The presence of the ester function with a long aliphatic chain makes the polymers soluble and allows them to be processed into films. The polymers can be doped using a solution of FeCl3 to the maximum electrical conductivity of 10−3 Ω−1 cm−1.  相似文献   

17.
Solution-processable electrochromic polymers (ECPs) with high performance are urgently needed for extensive applications. Nevertheless, they suffer from slow switching speed because of low ionic conductivities. Herein, we present an effective strategy to improve the contrast and switching speed in ECPs via facile side-chain engineering. A novel electrochromic thieno[3,2-b]thiophene-based polymer (PmOTTBTD) is designed and successfully synthesized by introducing oligo(ethylene oxide) side chains with high ionic conductivity. Compared to the counterpart POTTBTD without modification by oligo(ethylene oxide) chains, PmOTTBTD demonstrates nearly double contrast (42 % vs. 24 %) with a fast oxidation switching process that just takes half of the time when detected under 400 nm, as well as much higher coloration efficiencies (e. g. 239.04 cm2 C−1 vs. 226.26 cm2 C−1 @ 400 nm and 314.04 cm2 C−1 vs. 174.00 cm2 C−1 @ 650∼700 nm). Besides, PmOTTBTD exhibits excellent stability with negligible decay after 3000 cycles. Our work suggests a facile strategy that could be adopted to realize high-performance ECPs via molecular design tuning.  相似文献   

18.
Based on a “TADF + Linker” strategy (TADF=thermally activated delayed fluorescence), demonstrated here is the successful construction of conjugated polymers that allow highly efficient delayed fluorescence. Small molecular TADF blocks are linked together using a methyl-substituted phenylene linker to form polymers. With the growing number of methyl groups on the phenylene, the energy level of the local excited triplet state (3LEb) from the delocalized polymer backbone gradually increases, and finally surpasses the charge-transfer triplet state (3CT). As a result, the diminished delayed fluorescence can be recovered for the tetramethyl phenylene containing polymer, revealing a record-high external quantum efficiency (EQE) of 23.5 % (68.8 cd A−1, 60.0 lm W−1) and Commission Internationale de l′Eclairage (CIE) coordinates of (0.25, 0.52). Combined with an orange-red TADF emitter, a bright white electroluminescence is also obtained with a peak EQE of 20.9 % (61.1 cd A−1, 56.4 lm W−1) and CIE coordinates of (0.36, 0.51).  相似文献   

19.
The electrical conductivies of the poly(alkynylsilane)s [C-SiR1R2-CC-Z]n (R1R2Si = Ph2Si, nOct(Me)Si, 2,3.4,5-tetraphenyl-1-sila-2,4-cyclopentene; Z = (hetero)aromatic group) doped with FeCl3 are found to lie in the range 10−9 < α < 10−3 S cm−1, whereas those of the undoped polymers are less than 10−10 S cm−1. The presence of Ph groups on Si leads to incresed conductivity.  相似文献   

20.
《化学:亚洲杂志》2018,13(14):1791-1796
The development of highly efficient bioorthogonal reactions is of paramount importance for the research fields of biomaterials and chemical biology. We found that the o,o′‐difluorinated aromatic azide was able to react with triphenylphosphine to produce water‐stable phosphanimine. To further improve the efficiency of this kind of nonhydrolysis Staudinger reaction, a tetrafluorinated aromatic azide was employed to develop a faster nonhydrolysis Staudinger reaction with a rate of up to 51 m −1 s−1, as revealed by high‐performance liquid chromatography (HPLC) analysis and fluorescence kinetics. As a proof‐of‐concept study, the highly efficient Staudinger reaction was successfully used for chemoselective fluorescence labeling of proteins and nucleic acids (DNA and RNA) as well as for protein polyethyleneglycol (PEG)ylation. We believe that this bioorthogonal reaction can provide a broadly useful tool for various bioconjugations.  相似文献   

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