Anticorrosion Performance of Epoxy Coatings Containing Small Amount of Inherently Conducting PEDOT/PSS on Hull Steel in Seawater

Corrosion protection of the hull steel by the conventional epoxy paint containing a small amount of commercial poly(3,4-ethylenedioxythiophene)/poly(styrene sulfonate)(PEDOT/PSS),which is one of the most popular and successful inherently conducting polymers as the corrosion inhibitor was studied.The corrosion behavior of the samples was investigated in seawater by electrochemical impedance spectroscopy and open circuit potential.Scanning electron microscopy was used to observe the surface morphology of the samples after corrosion.It was found that adding a small amount of PEDOT/PSS to the epoxy resin can significantly improve its corrosion protection.     

General synthesis of high-performing magneto-conjugated polymer core–shell nanoparticles for multifunctional theranostics

Recently,increasing attention has been paid to magneto-conjugated polymer core-shell nanopartides (NPs) as theranostic platforms.However,the utilization of surfactants and extra oxidizing agents with potential toxidty in synthesis,the lack of general methods for the controlled synthesis of various kinds of magnetic NP (MNP)@conjugated polymer NPs,and the difficulty of obtaining balanced magneto-optical properties have greatly limited the applications of magneto-conjugated polymers in theranostics.We developed an in situ surface polymerization method free of extra surfactants and oxidizing agents to synthesize MNP@polypyrrole (PPy) NPs with balanced,prominent magneto-optical properties.MNP@PPy NPs with an adjustable size,different shapes,and a controlled shell thickness were obtained using this method.The method was extended to synthesize other MNP-conjugated polymer core-shell NPs,such as MNP@polyaniline and MNP@poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS).We discuss the formation mechanism of the proposed method according to our experimental results.Finally,using the optical and magnetic properties of the obtained MNP@PEDOT:PSS NPs,in vivo multimodal imaging-guided hyperthermia was induced in mice,achieving an excellent tumor-ablation therapeutic effect.Our work is beneficial for extending the application of MNP-conjugated polymer core-shell NPs in the biomedical field.     

Poled Polyaniline Coated Piezo Composite Using Low Electric Field and Reduced Poling Time： A Functional Material

Composite films were prepared by two different routes： lead zirconate titanate （PZT） particles coated with polyaniline （PAni） dispersed in a polymeric matrix of polyvinylidene fluoride （PVDF）; and PZT particles and PAni powder dispersed separately in the polymer matrix. The electrical conductivity of the particles was controlled by the protonation and de-protonation of PAni in solution with controlled pH. The results indicate that the percolation threshold of the composite made of PZT coated with a conductive layer （PZT-PAni） is in the range of 20 vol.% to 30 vol.% of PZT-PAni. The PZT-PAni/PVDF composite redoped in solution with pH 3.7 showed the best results in terms of longitudinal piezoelectric coefficient （d33） in samples containing 30 vol.% of ceramic particles due to the equilibrium between conduction and poling effects on the composite. The poling process of the composite sample required just 5 MV/m electric field applied during 15 min. Furthermore, the composite was used as sensor in structural health monitoring （SHM）, showing the possibility to propose it as a functional material.     

Binary Co–Ni oxide nanoparticle-loaded hierarchical graphitic porous carbon for high-performance supercapacitors

Heteroatom doped graphitic porous carbon is highly desirable for electrochemical applications because of its excellent conductivity and high surface area. In this study, highly uniform Co-Ni oxide nanoparticleloaded B, N-doped hierarchical graphitic porous carbon was prepared through a dual pyrolysis process.Graphene dispersed chitosan hydrogel was first used as a precursor to fabricate the porous carbon(GCS–C)at 700℃. Co and Ni oxide nanoparticles were further anchored on the porous carbon through chemical reduction and calcined at high temperature. The structure of the porous carbon was optimized by the introduction of graphene to the chitosan hydrogel. The graphitic degree of the porous carbon was significantly improved by the Co and Ni species. The heteroatom B and N were found to be well doped in the composite. These features enable the composite to be an excellent candidate for supercapacitor electrodes. The composite demonstrates a high capacitance(1266.7 F g~(-1) at 1 A g~(-1)) and excellent stability.     

Reduced graphene oxide with a highly restored π-conjugated structure for inkjet printing and its use in all-carbon transistors

An inkjet-printed graphene film is of great importance for next-generation flexible, low cost and high performance electronic devices. However, due to the limitation of the inkjet printing process, the electrical conductivity of inkjet-printed graphene films is limited to N10 S＇cm-1, and achieving a high conductivity of the printed graphene films remains a big challenge. Here, we develop a ＂weak oxidation- vigorous exfoliation＂ strategy to tailor graphene oxide （GO） for meeting all the requirements of highly conductive inkjet-printed graphene films, including a more intact carbon plane and suitable size. The -conjugated structure of the resulting graphene has been restored to a high degree, and its printed films show an ultrahigh conductivity of -420 S-cm-I, which is tens of times higher than previously reported results, suggesting that, aside from developing a highly efficient reduction method, tuning the GO structure could be an alternative way to produce high quality graphene sheets. Using inkjet-printed graphene patterns as source/drain/gate electrodes, and semiconducting single-walled carbon nanotubes （SWCNTs） as channels, we fabricated an all-carbon field effect transistor which shows excellent performance （an on/off ratio of -104 and a mobility of -8 cm2＂V-l＇s-1） compared to previously reported CNT-based transistors, promising the use of nanocarbon materials, graphene and SWCNTs in printed electronics, especially where high performance and flexibility are needed.     

Graphene film for thermal management:A review

Thermal conductivity and thermal dissipation are of great importance for modern electronics due to the increased transistor density and operation frequency of contemporary integrated circuits.Due to its exceptionally high thermal conductivity,graphene has drawn considerable interests worldwide for heat spreading and dissipation.However,maintaining high thermal conductivity in graphene laminates(the basic technological unit)is a significant technological challenge.Aiming at highly thermal conductive graphene films(GFs),this prospective review outlines the most recent progress in the production of GFs originated from graphene oxide due to its great convenience in film processing.Additionally,we also consider such issues as film assembly,defect repair and mechanical compression during the post-treatment.We also discuss the thermal conductivity in in-plane and through-plane direction and mechanical properties of GFs.Further,the current typical applications of GFs are presented in thermal management.Finally,perspectives are given for future work on GFs for thermal management.     

Multifunctional organically modified graphene with super-hydrophobicity

In order to bring graphene materials much closer to real world applications, it is imperative to have simple, efficient and eco-friendly ways to produce processable graphene derivatives. In this study, a hydrophilic low-temperature thermally functionalized graphene and its super-hydrophobic organically modified graphene derivative were fabricated. A unique structural topology was found and some of the oxygen functionalities were retained on the thermally functionalized graphene surfaces, which facilitated the subsequent highly effective organic modification reaction and led to the super-hydrophobic organically modified graphene with multi functional applications in liquid marbles and polymer nanocomposites. The organic modification reaction also restored the graphenic conjugated structure of the thermally functionalized graphene, particularly for organic modifiers having longer alkyl chains, as confirmed by various characteri- zation techniques such as electrical conductivity measurements, ultraviolet/visible spectroscopy and selected area electron diffraction. The free-standing soft liquid marble was fabricated by wrapping a water droplet with the super-hydrophobic organically modified graphene, and showed potential for use as a microreactor. As for the polymer nanocomposites, a strong interfacial adhesion is believed to exist between an organic polymer matrix and the modified graphene because of the organophilic coating formed on the graphene base, which resulted in large improvements in the thermal and mechanical properties of the polymer nanocomposites with the modified graphene, even at very low loading levels. A new avenue has therefore been opened up for large-scale production of processable graphene derivatives with various practicable applications.     

Preparation and Properties of Asphalt Modified with a Composite Composed of Waste Package Poly（vinyl chloride） and Organic Montmorillonite

A composite composed of waste package poly（vinyl chloride）（WPVC） and organic montmorillonite（OMMT） was prepared by coextrusion, which is used for modifying asphalt. The micromorphology of the WPVC/OMMT composite and its effect on the macroscopic properties of asphalt were studied using a fluorescent microscope and an X-ray diffractometer（XRD）. The introduction of OMMT allows the WPVC to be good dispersed in the asphalt matrix, as demonstrated by differential scanning calorimetry（DSC） and Fourier transform infrared spectroscopy（FTIR） analysis. The results indicate that asphalt modified by WPVC/OMMT composites with low OMMT content results in better high-temperature storage stability and physical properties of modified asphalt.     

Transport Properties of K_xV_2O_5·nH_2O Nanocrystalline Films

Five different compositions of K x V 2 O 5 ·nH 2 O(where x=0.00,0.0017,0.0049,0.0064 and 0.0091 mol) were prepared by the sol-gel process.Electrical conductivity and thermoelectric power were measured parallel to the substrate surface in the temperature range of 300-480 K.The electrical conductivity showed that all samples were semiconductors and that conductivity increased with increasing K content.The conductivity of the present system was primarily determined by hopping carrier mobility.The carrier density was evaluated as well.The conduction was confirmed to obey non-adiabatic small polaron hopping.The thermoelectric power or Seebeck effect,increased with increasing K ions content.The results obtained indicated that an n-type semiconducting behavior within the temperature range was investigated.     

Scalable arrays of chemical vapor sensors based on DNA-decorated graphene

Arrays of chemical vapor sensors based on graphene field effect transistors functionalized with single-stranded DNA have been demonstrated. Standard photolithographic processing was adapted for use on large-area graphene by including a metal protection layer, which protected the graphene from contamination and enabled fabrication of high quality field-effect transistors （GFETs）. Processed graphene devices had hole mobilities of 1,640 ± 250 cm2.V-1.s-1 and Dirac voltages of 15 ± 10 V under ambient conditions. Atomic force microscopy was used to verify that the graphene surface remained uncontaminated and therefore suitable for controlled chemical functionalization. Single-stranded DNA was chosen as the functionalization layer due to its affinity to a wide range of target molecules and π-π stacking interaction with graphene, which led to minimal degradation of device characteristics. The resulting sensor arrays showed analyte- and DNA sequence-dependent responses down to parts-per-billion concentrations. DNA/GFET sensors were able to differentiate among chemically similar analytes, including a series of carboxylic acids, and structural isomers of carboxylic acids and pinene. Evidence for the important role of electrostatic chemical gating was provided by the observation of understandable differences in the sensor response to two compounds that differed only by the replacement of a （deprotonating） hydroxyl group by a neutral methyl group. Finally, target analytes were detected without loss of sensitivity in a large background of a chemically similar, volatile compound. These results motivate further development of the DNA/graphene sensor family for use in an electronic olfaction system.     

Efficient TCO-free organic solar cells with modified poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) anodes

Organic photovoltaic cells (OPVs) with a highly conductive poly 3,4-ethylenedioxythiophene:poly styrenesulfonate (PEDOT:PSS) layer as an anode and that were modified with the addition of some organic solvents such as sorbitol (So), dimethyl sulfoxide (DMSO), N-methyl-pyrrolidone (NMP), dimethylformamide (DMF), and ethylene glycol (EG) were fabricated without the use of transparent conducting oxide (TCO). The conductivity of the PEDOT:PSS film that was modified with each additive was enhanced by three orders of magnitude. According to the atomic force microscopy (AFM) study, the conductivity enhancement might have been related to the better connections between the conducting PEDOT chains. The TCO-free solar cells with a modified PEDOT:PSS layer and an active layer composed of poly (3-hexylthiophene) (P3HT) and phenyl [6, 6] C61 butyric acid methyl ester (PCBM) performed as well as the indium-tin-oxide (ITO)-based organic solar cells. The power conversion efficiency (PCE) of the organic solar cells with a DMSO-, So + DMSO-, and EG-modified PEDOT:PSS layer reached 3.51, 3.64, and 3.77%, respectively, under an illumination of AM 1.5 (100 mW/cm2).     

Polymeric anodes from poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) for 3.5% efficient organic solar cells

We present highly efficient indium tin oxide free polymer solar cells based on poly-(3-hexylthiophene-2,5-diyl) and C₆₁-bis-butric-acid-methyl-ester (P3HT:bisPCBM) comprising a polymeric anode from highly conductive poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) formulations. The film conductivity was optimized by various additives. We found conductivities of almost 600 S/cm upon the addition of dimethylsulfoxide. The wetting properties of different PEDOT:PSS formulations were investigated by contact angle measurements. The optimized high conductivity in combination with the good film forming properties allow for the fabrication of highly efficient organic solar cells with an external power conversion efficiency of 3.5% with PEDOT:PSS as polymeric anode.     

Hybrid energy cell for simultaneously harvesting wind,solar, and chemical energies

We report a hybrid energy cell that can simultaneously or individually harvest wind, solar, and chemical energies to power some electronic devices. By utilizing the wind driven relative rotations between a polytetrafluoroethylene film and an etched A1 film attached on two acrylic tubes, the fabricated triboelectric nanogenerator （TENG） can deliver an open-circuit voltage of about 90 V, a short-circuit current density of about 0.5 mA/m2, and a maximum power density of 16 mW/m2, which is capable of directly lighting up 20 blue light- emitting-diodes （LEDs）. By integrating a TENG, a solar cell, and an electrochemical cell, a hybrid energy cell has been fabricated to simultaneously scavenge three different types of energies. As compared with the individual energy units, the hybrid energy cell exhibited much better performance in charging a capacitor. Moreover, we also demonstrated that the hybrid energies generated can be stored in a Li-ion battery for powering a commercial wind speed sensor and a temperature sensor. This work represents significant progress toward practical applications of hybrid energy cells, providing potential solutions for simul- taneously scavenging wind, solar, and chemical energies.     

Highly flexible and transparent conducting silver nanowire/ZnO composite film for organic solar cells

High efficiency and flexible inverted organic solar cells have been fabricated using solution-processed silver nanowire/zinc oxide composite transparent electrodes. The transparent electrodes showed a low sheet resistance of -13 ff）.sq-1 and high transmittance of -93% as well as superior mechanical flexibility. Power conversion efficiencies of -7.57% and -7.21% were achieved for devices fabricated on glass and plastic substrate, respectively. Moreover, the flexible devices did not show any degradation in their performance even after being folded with a radius of-480 μm.     

Construction and Characterization of Dye-Sensitized Solar Cells

This work describes the development of solar cells manufactured with different natural dyes, with the purpose to determine their photoelectrochemical properties, employing for that virtual instrumentation. Data acquisitions and statistical process of the same, are realized through graphical programming software. The system has facilities for measurements, acquisitions and to see permanently in the computer display, information about the performance of the solar cells, as well as environmental parameters such as; temperature and the I-V characteristic curve of the solar cell. This monitoring system pretends to be part of a permanent station for monitoring variables of the manufactured solar cells.     

High-performance planar heterojunction perovskite solar cells： Preserving long charge carrier diffusion lengths and interracial engineering

We demonstrate that charge carrier diffusion lengths of two classes of perovskites, CH3NH3PbI3-xClx and CH3NH3PbI3, are both highly sensitive to film processing conditions and optimal processing procedures are critical to preserving the long carrier diffusion lengths of the perovskite films. This understanding, together with the improved cathode interface using bilayer-structured electron transporting interlayers of [6,6]-phenyl-C61-butyric acid methyl ester （PCBM）/ZnO, leads to the successful fabrication of highly efficient, stable and reproducible planar heterojunction CH3NH3PbI3-xCl2 solar cells with impressive power-conversion efficiencies （PCEs） up to 15.9%. A 1-square-centimeter device yielding a PCE of 12.3% has been realized, demonstrating that this simple planar structure is promising for large-area devices.     

Structural and Optoelectronic Properties of Nanostructured ITO Thin Films Deposited by Chemical Spray Pyrolysis Technique

In this study, the spray pyrolysis method is used to generate an indium tin oxide （ITO） thin film on a glass substrate. In2O3 layers were deposited and doped with tin at different doping concentration ranging from 2% to 6%. ITO thin films for application in thin-film silicon solar cells with superior structure and optical properties （grain size ranging from 44 to 84 nm; transparency of〉 87%） have been investigated. This investigation elucidates the properties of ITO thin films used as antireflection front electrodes in p-n j unction Si solar cells. Microstructure, surface morphology, optoelectrical and optical properties of these films were then characterized and analyzed. Next, the effects of doping concentration of ITO film growth were discussed. The ITO thickness was optimized considering that the refractive index of Si emitter layer optimizes its optical characteristics and p-n junction solar cell spectral response. The best increasing in p-n junction solar cell conversion efficiency was 4% with an open circuit voltage （Voc） of 0.425 V, fill factor （FF） of 0.47, and short circuit current density （Jsc） of 0.91 mA/cm2.     

Photoelectrochemical Performance of Nb-doped TiO2 Nanoparticles Fabricated by Hydrothermal Treatment of Titanate Nanotubes in Niobium Oxalate Aqueous Solution

Nb-doped TiO2 nanoparticles were prepared by hydrothermal treatment of titanate nanotubes in niobium oxalate aqueous solution.The effect of Nb doping and rutile content on the photoelectrochemical performance based on TiO2 powder electrodes was investigated.The results show that Nb-doped TiO2 with a small amount of rutile exhibits the enhanced photoelectric conversion efficiency for dye-sensitized solar cell.The highest photoelectric conversion efficiency of 8.53%is obtained for 1%Nb—TiO2 containing a small amount of rutile.When a small amount of rutile contained in 2%Nb—TiO2,a higher photoelectric conversion efficiency of8.77%is achieved.     

Plasmon-enhanced Performance of Dye-sensitized Solar Cells Based on Electrodeposited Ag Nanoparticles简

In the present work,pulse current deposition is used to deposit evenly distributed and uniformly sized Ag nanoparticles onto a TiO_2 nanotube array as photoelectrode in dye-sensitized solar cells(DSSCs),and the size and amount of loading Ag nanoparticles are controlled by the pulse deposition time.Due to the enhanced light absorption and electron—hole separation caused by plasmon effect,DSSCs based on Ag-modified TiO_2nanotube arrays show higher energy conversion efficiencies than those based on bare nanotubes with the same tube length.Particularly,DSSC based on nanotubes modified using pulse deposition time 1 s/3 s delivers the highest energy conversion efficiency of 1.68%and the largest short-circuit current of 4.37 mA/cm~2,while DSSC consisting of bare nanotubes exhibits efficiency of 1.20%and short-circuit current of2.27 mA/cm~2,which represents a 40%enhancement of cell efficiency in DSSC based on Ag-modified TiO_2nanotubes.It is also noted that overly long pulse deposition time will not further increase DSSC efficiency due to agglomeration of Ag particles.For example,when the pulse deposition time is increased to 2 s/6 s,DSSC based on Ag-modified nanotubes exhibits a lower efficiency of 1.42%.Moreover,high-concentration TiCl_4treatment on TiO_2 nanotube arrays can further increase the energy conversion efficiencies to 3.82%and2.61%for DSSC based on Ag-modified TiO_2 nanotubes and DSSC based on bare TiO_2 nanotubes,respectively,by significantly creating more surface area for dye loading.     

Solution properties of poly(decylmethacrylate)s

Samples of poly(decylmethacrylate)s (PDMA) of a narrow molecular weight distribution were characterized by means of light-scattering, osmotic pressure, intrinsic viscosity and gelpermeation chromatography. The Kuhn-Mark-Houwink equation for molecularly uniform PDMA in THF at 25°C was calculated to be log [η] (ml/g) = ?2.67 + 0.80 logM (g/mol). The following Θ-solvents were found: 2-propanol, 2-propylacetate, 1-butanol and 1-pentanol. The molecular weight dependence of the demixing behaviour yields a Θ-temperature of 9.6°C for 1-pentanol and of 37.4°C for 1-butanol. Flow curves were measured in various solvents of different thermodynamic quality. A first valuation of the observed non-Newtonian behaviour is given.