Thermoelectric properties were investigated for the films of electrically conductive doped polyanilines. The thermoelectric performance, evaluated by thermoelectric figure-of-merit (ZT = T (S2σ) / κ), of various protonic acid-doped polyaniline bulk films was found to depend on the electrical conductivity σ of the film. Thus, the higher the electrical conductivity, the higher the figure-of-merit is, because the thermal conductivity κ of polyaniline films does not depend on the electrical conductivity. Among the conductive bulk films of polyaniline, the highest figure-of-merit (ZT = 1 × 10−4) was observed for (±)-10-camphorsulfonic acid (CSA)-doped polyaniline in an emeraldine form (σ - 188 S cm−1) at room temperature. The multilayered film, composed of electrically insulating emeraldine base layers and electrically conducting CSA-doped emeraldine salt layers, exhibited 6 times higher ZT at 300 K than that of a bulk film of CAS-doped polyaniline, showing the highest ZT value of 1.1 × 10−2 at 423 K. Stretching of the CAS-doped polyaniline film also increased the figure-of-merit of doped polyaniline films along the direction of the stretching. 相似文献
Highly conductive poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) films as transparent electrodes for organic light‐emitting diodes (OLEDs) are doped with a new solvent 1,3‐dimethyl‐2‐imidazolidinone (DMI) and are optimized using solvent post‐treatment. The DMI doped PEDOT:PSS films show significantly enhanced conductivities up to 812.1 S cm−1. The sheet resistance of the PEDOT:PSS films doped with DMI is further reduced by various solvent post‐treatment. The effect of solvent post‐treatment on DMI doped PEDOT:PSS films is investigated and is shown to reduce insulating PSS in the conductive films. The solvent posttreated PEDOT:PSS films are successfully employed as transparent electrodes in white OLEDs. It is shown that the efficiency of OLEDs with the optimized DMI doped PEDOT:PSS films is higher than that of reference OLEDs doped with a conventional solvent (ethylene glycol). The results present that the optimized PEDOT:PSS films with the new solvent of DMI can be a promising transparent electrode for low‐cost, efficient ITO‐free white OLEDs.
We report the first ion implantation doping studies on high-temperature ladder polymers and show that insulting films of the benzimidazobenzophenanthroline-type ladder polymer (BBL) can be doped by boron, argon, and krypton implantation to conductivities as high as 224 S/cm at a dose of 4.0 × 1016/cm2 while retaining the excellent mechanical properties of the pristine films. Effects of dose (ions/cm2) and beam current density (microamps/cm2) on electrical conductivity at fixed ion energies are reported. The temperature dependence of the conductivity indicates that the implanted ladder polymer films are semiconductors. Spatially selective implantation, creating regions of conducting lines in an insulating matrix, which suggests microelectronic device applications of the ladder polymers, is demonstrated. 相似文献
The electrical conductivity of aromatic and heteroaromatic polymers as well as polymers with aromatic, heteroaromatic and vinylene units in the main chain, can be enhanced by oxidation. In a single electron transfer reaction, a polymer with a salt structure (“doped polymer”) can be formed. Such polymers can also be prepared in a one-step reaction from low-molecular weight compounds by oxidants, as well as by electrochemical reaction. Electrochemically produced samples have higher electrical conductivities (as high as 6298K = 0,5 Ω−1 · cm−1) than samples made by chemical oxidation from the same starting material. 相似文献
Thick, uniform, easily processed, highly conductive polymer films are desirable as electrodes for solar cells as well as polymer capacitors. Here, a novel scalable strategy is developed to prepare highly conductive thick poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate (HCT‐PEDOT:PSS) films with layered structure that display a conductivity of 1400 S cm?1 and a low sheet resistance of 0.59 ohm sq?1. Organic solar cells with laminated HCT‐PEDOT:PSS exhibit a performance comparable to the reference devices with vacuum‐deposited Ag top electrodes. More importantly, the HCT‐PEDOT:PSS film delivers a specific capacitance of 120 F g?1 at a current density of 0.4 A g?1. All‐solid‐state flexible symmetric supercapacitors with the HCT‐PEDOT:PSS films display a high volumetric energy density of 6.80 mWh cm?3 at a power density of 100 mW cm?3 and 3.15 mWh cm?3 at a very high power density of 16160 mW cm?3 that outperforms previous reported solid‐state supercapacitors based on PEDOT materials. 相似文献
Plasma polymerization of some cyano-containing organic compounds was carried out at 13.56 MHz from the gas phase. The resulting polymer films were smooth and pinhole free. The electrical conductivities of the polymer films varied from 10?12 to 10?7 S cm?1 depending upon which cyano-containing monomer was used. The Al/polymer film/ITO (indium-tin oxide) sandwich cells made from the films demonstrated a photovoltaic effect, and some of them showed good rectifying behavior. Infrared spectroscopy (IR) and ultraviolet spectroscopy (UV) were utilized to characterize the structure of the product polymers. The effects of the original structure in the starting monomers on the structure of the resulting polymers are investigated. The influence of incident light intensity on the photovoltaic characteristics was also investigated. 相似文献
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
Composite films of poly(3,4‐ethylenedioxythiophene) (PEDOT)‐coated over functionalized multiwalled coiled and linear carbon nanotubes (CNTs) have been fabricated by a simple oxidative electropolymerization route. The nanotubular morphology of the polymer–CNT composite is responsible for the lower charge transfer impedance, lower internal resistance, and superior capacitive response in comparison to that shown by the control PEDOT film doped by trifluoromethanesulfonate ions. This facile electrochemistry exhibited by the PEDOT–CNT composite film ensues in a remarkably high coloration efficiency of 367 cm2 · C−1 at 550 nm, hitherto unrealized for PEDOT; thus demonstrating the huge potential the PEDOT–CNT composite film has as cathode for the entire spectrum of electrochromic devices.
A porous crystal family has been explored as alternatives of Nafion films exhibiting super-proton conductivities of ≥10−2 S cm−1. Here, the proton-conduction natures of a solution-processed film of nanoparticles (NPs) have been studied and compared to those of a Nafion film. A mono-particle film of Prussian-blue NPs is spontaneously formed on a self-assembled monolayer substrate by a one-step solution process. A low-temperature heating process of the densely packed, pinhole-free mono-particle NP film enables a maximum 105-fold enhancement of proton conductivity, reaching ca. 10−1 S cm−1. The apparent highest conductivity, compared to previously reported data of the porous crystal family, remains constant against humidity changes by an improved water-retention ability of the film. In our proposed mechanism, the high-performing solution-processed NP film suggests that heating leads to the self-restoration of hydrogen-bonding networks throughout their innumerable grain boundaries. 相似文献
A new method is described for the preparation of conducting Langmuir-Blodgett films based on tetrathialfulvalene (TTF) derivatives without long alkyl chain substitution. The mixed molecular system of behenic acid (BA) and oxygen-substituted TTF-type donor molecules such as 4,5-ethylenedioxy-4′,5′-ethylenedithio-tetrathiafulvalene (EOET) or bis-ethylenedioxy-tetrathiafulvalene (BO) provides a stable bilayer film at the air/water interface. In the LB films prepared by Y-type deposition, the donor molecules form mixed-valence dimers such as D+ D0, without secondary treatments. The maximum conductivities of the LB films reached 1.0S cm−1 (EOET + BA) and 25 S cm−1 (BO + BA) at room temperature. The surface pressure/area isotherms and Fourier transform infra-red spectra are also reported with regard to, respectively, film formation on the water surface and the mixed-valence dimer state under different molar ratios of the donors to B A. 相似文献
Poly(2-methoxyphenylene vinylene) has been synthesized by a four step reaction sequence beginning with the bromination of 2,5-dimethylanisole and proceeding to the formation of an intermediate sulfonium salt precursor polymer. The infrared and UV-visible spectra of the PPV derivative asymmetrically substituted on the phenyl ring are presented. Films of poly(2-methoxyphenylene vinylene) can be doped with iodine to give a conductivity of 1 S cm?1. Films doped with AsF5 exhibited activated charge transport behavior with room temperature conductivities of about 100 S cm?1. 相似文献
Proton conductivities of layered solid electrolytes can be improved by minimizing strain along the conduction path. It is shown that the conductivities (σ) of multilayer graphene oxide (GO) films (assembled by the drop‐cast method) are larger than those of single‐layer GO (prepared by either the drop‐cast or the Langmuir‐Blodgett (LB) method). At 60 % relative humidity (RH), the σ value increases from 1×10−6 S cm−1 in single‐layer GO to 1×10−4 and 4×10−4 S cm−1 for 60 and 200 nm thick multilayer films, respectively. A sudden decrease in conductivity was observed for with ethylenediamine (EDA) modified GO (enGO), which is due to the blocking of epoxy groups. This experiment confirmed that the epoxide groups are the major contributor to the efficient proton transport. Because of a gradual improvement of the conduction path and an increase in the water content, σ values increase with the thickness of the multilayer films. The reported methods might be applicable to the optimization of the proton conductivity in other layered solid electrolytes. 相似文献
Thermal transporting properties of electrically conductive polyaniline films were first investigated in wide range of temperatures
above room temperature as organic thermoelectric materials. Thermal conductivities of various protonic acid-doped polyaniline
films were measured by combination of a laser flash method and a differential scanning calorimeter in relation with electrical
conductivity and a kind of dopant. The thermal conductivities thus measured are in the range of conventional organic polymers,
indicating that the doped polyaniline films have extremely low thermal conductivities among electrically conductive materials,
and have correlation with neither electrical conductivity, nor a kind of dopant. Consequently the polyaniline film, which
shows very high electrical conductivity, has comparable thermoelectric figure-of-merit (ZT) with feasible inorganic thermoelectric materials such as iron silicide.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
When homogeneously grafted as thin films on small band-gap inorganic semiconductors (n-GaAs, n-CdS), organic conjugated polymers such as poly-methylthiophene afford interesting new structures. In their doped conducting state, these polymer films bring a long-term protection of these semiconductors against their photocorrosion in aqueous medium, and the subsequent inclusion of metallic aggregates in these films allows increased catalytic activity for achieving photoelectrochemical reactions. In their undoped semiconducting state, they lead to the realization of “organic-on-inorganic” p-n junctions which show very low leakage current and high allowed current density. As photovoltaic cell, an energy conversion efficiency of 17.5% has been obtained under 100 mW.cm−2 irradiation with a p-PMeT/n-GaAs cell. The larger number of work already devoted to organic conjugated polymers such as polyacetylene, polypyrrole, polythiophene, has shown that these compounds can be switched between a doped oxidized state, with a nearly metallic conductivity, σ ∼ 102-103S.cm−1, and an undoped neutral state which presents semiconducting properties, σ ∼ 10−7 -10−9 S. cm−1. Either as free standing film or grafted on an electrode, these polymers exhibit interesting organic electrode properties which have been widely characterized. On the other hand much less is known on their behavior when deposited on inorganic semiconductors. In the following, this area will be discussed on two examples, the protection of narrow band-gap semiconductors against their photo-degradation in aqueous solution, and the new junction properties presented by “organic-on-inorganic” electronic devices. 相似文献