Wenyao Yang

In situ polymerization deposition of porous conducting polymer on reduced graphene oxide for gas sensor.

Porous conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) nanocomposite prepared on reduced graphene oxide (RGO) film was used as efficient chemiresistor sensor platform for NO2 detection. The comparable electrical performance between RGO and porous PEDOT nanostructure, the large surface area and opening porous structure of this RGO/porous PEDOT nanocomposite resulted in excellent synergistic effect. The gas sensing performance revealed that, in contrast to bare RGO, the RGO/porous PEDOT exhibited the enhanced sensitivity (2 orders of magnitude) as well as response and recovery performance. As a result of the highly uniform distribution of PEDOT porous network and excellent synergetic effect between RGO and porous PEDOT, this nanocomposite based sensor exhibited higher selectivity to NO2 in contrast to other oxidant analyte gases, e.g., HCl, H2S and SO2.

Vapor phase polymerization deposition of conducting polymer/graphene nanocomposites as high performance electrode materials.

In this paper, we report chemical vapor phase polymerization (VPP) deposition of novel poly(3,4-ethylenedioxythiophene) (PEDOT)/graphene nanocomposites as solid tantalum electrolyte capacitor cathode films. The PEDOT/graphene films were successfully prepared on porous tantalum pentoxide surface as cathode films through the VPP procedure. The results indicated that the high conductivity nature of PEDOT/graphene leads to the decrease of cathode films resistance and contact resistance between PEDOT/graphene and carbon paste. This nanocomposite cathode film based capacitor showed ultralow equivalent series resistance (ESR) ca. 12 mΩ and exhibited better capacitance-frequency performance than the PEDOT based capacitor. The leakage current investigation revealed that the device encapsulation process does not influence capacitor leakage current, indicating the excellent mechanical strength of PEDOT-graphene films. The graphene showed a distinct protection effect on the dielectric layer from possible mechanical damage. This high conductivity and mechanical strength graphene based conducting polymer nanocomposites indicated a promising application future for organic electrode materials.

Porous conducting polymer and reduced graphene oxide nanocomposites for room temperature gas detection

We report the chemical in situ deposition of a porous conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) on reduced graphene oxide (RGO) film as an efficient chemiresistor sensor platform for room temperature NH3 gas detection. A good covering of porous PEDOT on RGO was achieved through a simple baking treatment during the in situ polymerization of PEDOT. The good covering of porous PEDOT on the RGO surface was confirmed by SEM, UV-Vis spectra, and FT-IR spectra methods. The gas sensing performance revealed that, in contrast to bare RGO and common PEDOT, the porous PEDOT/RGO based gas sensor exhibited an obvious sensitivity enhancement as well as response/recovery performance. The large surface area and very open structure of the porous PEDOT resulted in an excellent synergistic effect between PEDOT and RGO during the gas sensing process. As a result of the uniform distribution of the PEDOT porous network on the RGO sheets, this nanocomposite based sensor also exhibited higher selectivity to NH3 in contrast to other reductive analyte gases.

Ordered and ultrathin reduced graphene oxide LB films as hole injection layers for organic light-emitting diode

In this paper, we demonstrated the utilization of reduced graphene oxide (RGO) Langmuir-Blodgett (LB) films as high performance hole injection layer in organic light-emitting diode (OLED). By using LB technique, the well-ordered and thickness-controlled RGO sheets are incorporated between the organic active layer and the transparent conducting indium tin oxide (ITO), leading to an increase of recombination between electrons and holes. Due to the dramatic increase of hole carrier injection efficiency in RGO LB layer, the device luminance performance is greatly enhanced comparable to devices fabricated with spin-coating RGO and a commercial conducting polymer PEDOT:PSS as the hole transport layer. Furthermore, our results indicate that RGO LB films could be an excellent alternative to commercial PEDOT:PSS as the effective hole transport and electron blocking layer in light-emitting diode devices.

Vapor Phase Polymerization Deposition Conducting Polymer Nanocomposites on Porous Dielectric Surface as High Performance Electrode Materials

We report chemical vapor phase polymerization (VPP) deposition of poly(3,4-ethylenedioxythiophene) (PEDOT) and PEDOT/graphene on porous dielectric tantalum pentoxide (Ta2O5) surface as cathode films for solid tantalum electrolyte capacitors. The modified oxidant/oxidant-graphene films were first deposited on Ta2O5 by dip-coating, and VPP process was subsequently utilized to transfer oxidant/oxidant-graphene into PEDOT/PEDOT-graphene films. The SEM images showed PEDOT/PEDOT-graphene films was successfully constructed on porous Ta2O5 surface through VPP deposition, and a solid tantalum electrolyte capacitor with conducting polymer-graphene nano-composites as cathode films was constructed. The high conductivity nature of PEDOT-graphene leads to resistance decrease of cathode films and lower contact resistance between PEDOT/graphene and carbon paste. This nano-composite cathode films based capacitor showed ultralow equivalent series resistance (ESR) ca. 12Ω and exhibited excellent capacitance-frequency performance, which can keep 82% of initial capacitance at 500 KHz. The investigation on leakage current revealed that the device encapsulation process has no influence on capacitor leakage current, indicating the excellent mechanical strength of PEDOT/PEDOT-gaphene films. This high conductivity and mechanical strength of graphene-based polymer films shows promising future for electrode materials such as capacitors, organic solar cells and electrochemical energy storage devices.

Detection of Volatile Organic Compounds Using Langmuir-Blodgett Films of Zinc-Porphyrin and Zinc-Phthalocyanine

Detection of volatile organic compounds (VOCs) by electronic optical nose based on sensing thin films is becoming more interesting in modern industry and daily life. The thin films of zinc-porphyrin and zinc-phthalocyanine fabricated by Langmuir-Blodgett (LB) technique onto quartz substrates have been used as sensing elements for electronic optical nose application. Absorption spectra range of the both organic elements in a chloroform solution and the LB solid state thin films were acquired by using a UV-1700 spectrometer. As an electronic gas sensing test, the optical absorbance performance after the exposure of LB films to different VOCs, and dry air was investigated. The results indicated that the ZnTPP and ZnPc LB films showed different gas sensitivity due to different molecule structure. Besides, a 2 × 1 colorimetric array is fabricated by immobilizing sensing thin film on a silica substrate, and the vapor molecules of pyridine and methanol can be easily detected.

Chemical vapor phase polymerization deposition of layer-ordered conducting polymer nanostructure for hole injection layer

Layer-ordered and ultrathin films of conducting polymer poly(3,4-ethylene dioxythiophene) (PEDOT) was prepared through a chemical vapor phase polymerization method. The chemical polymerization of 3, 4-ethylenedioxythiophene monomer was initiated in as-prepared oxidant LB films,and PEDOT nanofilms with layer-ordered structure was constructed. UV-Vis absorption spectrum and Fourier transform infrared spectroscopy was used to confirm an interface polymerization of PEDOT in as-prepared LB films. The results of X-ray diffraction and secondary ion mass spectrometry revealed that conductive PEDOT ultrathin layers were well located at different planes of LB films. The film deposition surface pressure and chemical polymerization time of PEDOT monomer in as-prepared LB films showed distinct influence on surface morphology and conductive performance of the polymerized PEDOT LB films. This layer-ordered conducting polymer ultrathin films was deposited on ITO surface as hole injection layer for organic light-emitting diodes, and the luminescence performance of devices was improved as well.

Retraction of “Vapor Phase Polymerization Deposition of Conducting Polymer/Graphene Nanocomposites as High Performance Electrode Materials”

T authors retract the article “Vapor Phase Polymerization Deposition of Conducting Polymer/Graphene Nanocomposites as High Performance Electrode Materials” (ACS Appl. Mater. Interfaces 2013, 5 (10), 4350−4355, DOI: 10.1021/am4003815) due to a duplicate prior publication: “Vapor Phase Polymerization Deposition Conducting Polymer Nanocomposites on Porous Dielectric Surface as High Performance Electrode Materials” (Micro Nano Lett. 2013, 5 (1), 40−46, DOI: 10.1007/BF03353730). Retraction