PSS Nanocomposites Research Articles

High-Performance PEDOT:PSS/Hexamethylene Diisocyanate-Functionalized Graphene Oxide Nanocomposites: Preparation and Properties.

Graphene oxide (GO) has emerged as an ideal filler to reinforce polymeric matrices owing to its large specific surface area, transparency, flexibility, and very high mechanical strength. Nonetheless, functionalization is required to improve its solubility in common solvents and expand its practical uses. In this work, hexamethylene diisocyanate (HDI)-functionalized GO (HDI-GO) has been used as filler of a conductive polymer matrix, poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS). The nanocomposites have been prepared via a simple solution casting method, and have been characterized by scanning electron microscopy (SEM), UV–Vis and Raman spectroscopies, X-ray diffraction (XRD), thermogravimetric analysis (TGA), tensile tests, and four-point probe measurements to get information about how the HDI-GO functionalization degree (FD) and the HDI-GO concentration in the nanocomposite influence the final properties. SEM analysis showed a very homogenous dispersion of the HDI-GO nanosheets with the highest FD within the matrix, and the Raman spectra revealed the existence of very strong HDI-GO-PEDOT:PSS interactions. A gradual improvement in thermal stability was found with increasing HDI-GO concentration, with only a small loss in transparency. A reduction in the sheet resistance of PEDOT:PSS was found at low HDI-GO contents, whilst increasing moderately at the highest loading tested. The nanocomposites showed a good combination of stiffness, strength, ductility, and toughness. The optimum balance of properties was attained for samples incorporating 2 and 5 wt % HDI-GO with the highest FD. These solution-processed nanocomposites show considerably improved performance compared to conventional PEDOT:PSS nanocomposites filled with raw GO, and are highly suitable for applications in various fields, including flexible electronics, thermoelectric devices, and solar energy applications.

Gold nanoparticle-polymer nanocomposites synthesized by room temperature atmospheric pressure plasma and their potential for fuel cell electrocatalytic application

Conductive polymers have been increasingly used as fuel cell catalyst support due to their electrical conductivity, large surface areas and stability. The incorporation of metal nanoparticles into a polymer matrix can effectively increase the specific surface area of these materials and hence improve the catalytic efficiency. In this work, a nanoparticle loaded conductive polymer nanocomposite was obtained by a one-step synthesis approach based on room temperature direct current plasma-liquid interaction. Gold nanoparticles were directly synthesized from HAuCl4 precursor in poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS). The resulting AuNPs/PEDOT:PSS nanocomposites were subsequently characterized under a practical alkaline direct ethanol fuel cell operation condition for its potential application as an electrocatalyst. Results show that AuNPs sizes within the PEDOT:PSS matrix are dependent on the plasma treatment time and precursor concentration, which in turn affect the nanocomposites electrical conductivity and their catalytic performance. Under certain synthesis conditions, unique nanoscale AuNPs/PEDOT:PSS core-shell structures could also be produced, indicating the interaction at the AuNPs/polymer interface. The enhanced catalytic activity shown by AuNPs/PEDOT:PSS has been attributed to the effective electron transfer and reactive species diffusion through the porous polymer network, as well as the synergistic interfacial interaction at the metal/polymer and metal/metal interfaces.

The Improved Photocatalytic Ability for Ag3PO4 through the Use of a PEDOT:PSS Layer

We report in this study the improved photocatalytic ability and the photo-corrsion resistance of Ag3PO4. We have used PEDOT:PSS as an protective layer to create Ag3PO4/PEDOT:PSS nanocomposite photocatalyst. Ag(NH3)2 + and Na2HPO4 were used as the precursor to synthesize Ag3PO4. Precursor concentration and ratio were varied. A chemisorption method was then used to make Ag3PO4/PEDOT:PSS nanocomposites. Nanocomposites having different ratios Ag3PO4/PEDOT:PSS were prepared and investigated. Moreover, Triton-X was used as an additive for further enhancing the conductivity and catalytic power of the Ag3PO4/PEDOT:PSS nanocomposite. Methylene blue was used to study the photodegradation performance of the obtained photocatalyst. The photodegradation performance of such a novel nanocomposite is demonstrated.

GO/PEDOT:PSS nanocomposites: effect of different dispersing agents on rheological, thermal, wettability and electrochemical properties

In this work glucose (G), α-cyclodextrin (α-CD) and sodium salt of carboxymethyl cellulose (CMCNa) are used as dispersing agents for graphene oxide (GO), exploring the influence of both saccharide units and geometric/steric hindrance on the rheological, thermal, wettability and electrochemical properties of a GO/poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) nanocomposite. By acting on the saccharide-based additives, we can modulate the rheological, thermal, and wettability properties of the GO/PEDOT:PSS nanocomposite. Firstly, the influence of all the additives on the rheological behaviour of GO and PEDOT:PSS was investigated separately in order to understand the effect of the dispersing agent on both the components of the ternary nanocomposite, individually. Subsequently, steady shear and dynamic frequency tests were conducted on all the nanocomposite solutions, characterized by thermal, wettability and morphological analysis. Finally, the electrochemical properties of the GO/PEDOT composites with different dispersing agents for supercapacitors were investigated using cyclic voltammetry (CV). The CV results revealed that GO/PEDOT with glucose exhibited the highest specific capacitance among the systems investigated.

Controlled growth and spray deposition of silver nanowires for ITO‐free, flexible, and high brightness OLEDs

The next generation of electronic devices will require low cost materials and processing techniques that are fully compatible with flexible substrates and large area applications. Silver nanowires are promising candidates for many applications and can be processed by various solution‐based large area deposition techniques. In this work, high aspect ratio silver nanowires were synthesized via a polyol reduction of silver nitrate in the presence of a metal‐salt and a capping agent. The grown nanowires were spray coated and simply planarized with inkjet printed PEDOT:PSS to produce smooth and high performance nanocomposite electrodes suitable for industrial applications. The nanocomposite electrodes exhibit figure of merit values (σDC/σOP) of about 60, higher than the values required for industrial use (>35). High conductivity with high optical transparency was achieved by controlling the aspect ratio of the nanowires and their concentration in the films. The highly conductive and transparent electrodes were utilized to fabricate organic light emitting diodes, which exhibited high luminance (∼ 7 × 103 cd m−2) and performance comparable to a “benchmark” ITO electrode. The results show that the combination of the nanocomposite materials, together with the solution based techniques could pave the way towards flexible, solution processable, low cost, and large area device applications.ITO‐free OLEDs fabricated using solution processed Ag NW/PEDOT:PSS nanocomposites as transparent conductive electrode. Improving the aspect ratio of the grown nanowires along with controlling their density in the films allow for highly conductive and transparent nanocomposite electrodes. These nanocomposite samples are utilized as a direct replacement for ITO in OLEDs.

Carbon nanohorns functionalized PEDOT:PSS nanocomposites for dye sensitized solar cell applications

Single wall carbon nanohorns (SWCNH) functionalized poly 3,4-ethylene dioxythiophene:Polystyrene sulphonate (PEDOT:PSS) composites were developed by reaction of PEDOT:PSS with different weight ratio (0.05, 0.1, 0.2, 0.3, 0.4 wt%) of SWCNH, used as counter electrodes for dye sensitized solar cells (DSSC). Transmission electron microscopy confirms “dahlia” like flowers or buds, having an overall diameter of tens of nm. Cyclic-voltammetric studies of 0.3 wt% composite gives faster I−/I3− reaction rate, high surface area. Electrochemical impedance spectroscopy revealed series resistance (RS) and charge transfer resistance (Rct) of 0.3 wt% composite DSSC of 20.93, 83.79 Ω respectively, these values were lower compared with the other DSSCs. Photocurrent density–voltage measurements shown the enhanced conversion efficiency (η) of 4.70 % for 0.3 wt% composite, whereas for pure PEDOT:PSS η = 3.66 % and pristine SWCNH of η = 1.94 %. The improved conversion efficiency was due to the combinational superior electrocatalytic activity, reduced RS, Rct. This study reveals PEDOT:PSS with SWCNH composite films were possible low cost catalysts for DSSC applications.

Electrical properties of multi-walled carbon nanotubes/PEDOT:PSS nanocomposites thin films under temperature and humidity effects

The effect of temperature and humidity on the electrical properties of thin films based on multi-walled carbon nanotubes (MWCNTs) dispersed in sodium dodecylbenzene sulfonate (SDBS) and mixed with poly (3,4-ethylene dioxythiophene)–poly (4-styrenesulfonate) (PEDOT:PSS) were investigated systematically. The change in DC-resistivity was measured by 4-wire technique as a function of the temperature and the relative humidity (RH). The investigation of temperature influence shows semiconducting behavior in the temperature range from 20°C to 80°C. This behavior is due to the tunneling barrier, which is expected to dominate the overall film resistance in this temperature range. Moreover, the investigation of humidity effects at temperatures up to 60°C shows that the resistivity increases exponentially until 70% RH and then it starts to decrease sharply because of development of water layer on PEDOT:PSS film. This effect plays a minor role at high working temperature e.g. 70°C. Below the saturation point, the films act as a humidity sensor with high sensitivity around ∼0.07%RH.

Non-covalently functionalized single walled carbon nanotube/poly(3,4ethylenedioxythiophene):poly(styrenesulfonate) nanocomposites for organic photovoltaic cell

In this study, we developed a non-covalent functionalization method to disperse single walled CNTs (SWNTs) with minimal loss of electrical properties. SWNTs were non-covalently functionalized by 1-aminopyrene (AP-SWNTs), and covalently functionalized SWNTs (carboxylate-SWNTs) were fabricated by strong acid treatment for comparing the properties of functionalized SWNTs. By using functionalized SWNTs, SWNT/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) nanocomposites were fabricated as transparent conductive films. AP-SWNT/PEDOT:PSS nanocomposites showed higher electrical conductivity (sheet resistance: 634Ω/sq) at a similar optical transmittance compared to raw PEDOT:PSS (1555Ω/sq) and carboxylate SWNT/PEDOT:PSS nanocomposites (933Ω/sq) due to homogeneously dispersed AP-SWNTs in matrix with minimal damages during the functionalization. We also applied the AP-SWNT/PEDOT:PSS nanocomposites as a hole conducting layer in an organic photovoltaic cell (OPVC) application. Power conversion efficiency (PCE) of the OPVC using AP-SWNT/PEDOT:PSS was enhanced from 2.3% to 3.0% compared to an OPVC using raw PEDOT:PSS. The main reason for this enhancement of the PCE was thought to be the increase of JSC due to effective hole transport and collection by highly conductive, AP-SWNT/PEDOT:PSS nanocomposites.

Nonvolatile write-once-read-many-times memory device with functionalized-nanoshells/PEDOT:PSS nanocomposites

We have investigated the memory effect of the nanocomposites of functionalized carbon nanoshells (f-CNSs) mixed with poly(3,4-ethylenedioxythiophene) doped with polystyrenesulfonate (PEDOT:PSS) polymer. The f-CNSs were synthesized by the spray pyrolysis method and functionalized in situ with functional groups (OH, COOH, C–H, C–OH) with the aim of improving their compatibility in the aqueous dispersion of PEDOT:PSS. The current–voltage ( I – V ) sweep curves at room temperature for the Al/f-CNSs, for certain concentrations range, embedded in a PEDOT:PSS layer/Al devices showed electrical bistability for write-once-read-many-times (WORM) memory devices. The memory effect observed in the devices can be explained due to the existence of trapped charges in the f-CNSs/PEDOT:PSS layer. The carrier transport mechanisms for the memory devices is studied and discussed.

Improving Efficiency of Organic Photovoltaic Cells Using PEDOT:PSS and MWCNT Nanocomposites as a Hole Conducting Layer

In this study, polymeric nanocomposites of poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate) (PEDOT:PSS) and functionalized multi-walled carbon nanotubes (MWCNTs) were spin coated on a pre-patterned ITO glass and used as a hole conducting layer in organic photovoltaic cells. The multi-layered ITO/MWCNT-PEDOT:PSS/CuPc/C60/Al devices were fabricated to investigate the current density-voltage characteristics and power conversion efficiency. The power conversion efficiency obtained from the device with a concentration of 1.0 wt% MWCNT in the PEDOT:PSS layer was increased twice as those adopted from device without MWCNT doping in the PEDOT:PSS layer and current density-voltage characteristics was also improved well with incorporation of MWCNTs.

“One-pot” synthesis, characterization, and NH 3 sensing of Pd/PEDOT:PSS nanocomposite

In this letter, we report a novel route to prepare stable Pd/poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (Pd/PEDOT:PSS) colloid. With addition of PSS, the Pd/PEDOT:PSS aqueous dispersion was formed by simultaneous oxidation–reduction reaction between Pd(NO 3) 2 and ethylenedioxythiophene (EDOT) at room temperature. The morphologies of the Pd/PEDOT and Pd/PEDOT:PSS nanocomposites were characterized by transmission electron microscope. The Pd nanoparticles in the composites were identified with X-ray powder diffraction and UV/vis/NIR spectrum. The chemical structures of PEDOT were studied using FTIR spectra and UV/vis/NIR spectra. The results confirmed the formation of oxidized PEDOT polymer. The sensing property of the Pd/PEDOT:PSS thin film to the NH 3 vapor was investigated.

Fabrication and characterization of OLEDs using PEDOT:PSS and MWCNT nanocomposites

Nanocomposites of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) and multi-wall carbon nanotubes (MWCNTs) were investigated as hole injection layers in organic light-emitting diodes (OLEDs) consisting of a hole transport layer of N, N′-diphenyl- N, N′-di(m-tdyl)benzidine (TPD) and a light-emitting/electron transport layer of tris(8-hydroxyquinolinato)aluminium (Alq3) sandwiched between a transparent ITO anode based on polyethylene terephthalate (PET) substrate and a metal cathode. The OLEDs were fabricated by physical vapor deposition method and the current–voltage–luminescence ( I– V– L) characteristics of the devices were examined. It was found that high light intensity can be obtained by adopting nanocomposites of PEDOT:PSS and MWCNTs as hole injection layer of OLEDs. Reasons for the improved performance of the devices were discussed. The improved electric properties of the nanocomposites might be the reason for the improvement of OLED performance achieved by incorporating MWCNTs into hole injection layer of PEDPT:PSS.