Gamze Celik Cogal

Highly conductive polymer materials based multi-walled carbon nanotubes as counter electrodes for dye-sensitized solar cells

ABSTRACT Poly(3,4-ethylenedioxxythiophene) (PEDOT), polyaniline (PANI) and polythiophene (PTh) based multi-walled carbon nanotube (MWCNT) composites were successfully prepared using RF-rotating plasma grafting method. Morphological characterizations of composites were determined using scanning electron microscopy (SEM), which showed that conducting polymers (CPs) of PEDOT, PANI and PTh were coated on the surface of CNTs. The surface properties of the Carbon Nanotube (CNT) composites were also determined by using Infrared Spectra (FT-IR), X-ray Photon Spectra (XPS), and Scanning Electron Microscopy-Energy Dispersive X-ray Spectra (SEM-EDX) analysis. X-ray photon spectra results confirmed the formation of the composites. Composites of MWCNT were used in dye-sensitized solar cells (DSSCs) as counter electrodes and exhibited short-circuit photocurrent densities of 11.19, 10.70 and 8.54 mA/cm2 for PANI/MWCNT, PTh/MWCNT and PEDOT/CNT, respectively. GRAPHICAL ABSTRACT

Plasma-modified multiwalled carbon nanotubes with polyaniline for glucose biosensor applications

ABSTRACT Multiwalled carbon nanotube (MWCNT) was modified through plasma polymerization of aniline by applying different radio frequency (radio frequency (RF): 13.56 MHz) powers. The modified MWCNTs were investigated in terms of morphology, chemical structure, and thermal behaviors, indicating the formation of composites based on the surface modification of MWCNT with polyaniline (PANI). These composites were then used in amperometric glucose biosensor, which was constructed by immobilizing glucose oxidase on premodified Pt electrode with PANI/MWCNT composites. The biosensor based on the composite obtained under RF power of 60 W exhibited the high sensitivity of 54.91 µA mM−1 cm−2 to glucose. GRAPHICAL ABSTRACT

Plasma-based preparation of polyaniline/graphene and polypyrrole/graphene composites for dye-sensitized solar cells as counter electrodes

ABSTRACT This study presents the preparation of graphene (GR) nanocomposites with polyaniline (PANI) and polypyrrole (PPy) through the fast, versatile and environmentally friendly process of radio frequency (RF)-plasma polymerization. Morphological characterization of the nanocomposites is performed using scanning electron microscopy (SEM) and shows that the PANI and PPy conducting polymers coated the GR surface. The surface properties of the GR nanocomposites are determined using Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). The prepared GR nanocomposites are then used as counter electrodes in dye-sensitized solar cells (DSSCs). The conversion cell efficiencies for iodine-doped DSSC samples are found to be 0.086%, 5.41%, and 5.60% for I2-PANI, I2-PANI-GR and I2-PPy-GR, respectively, while the corresponding undoped samples reaches power conversion efficiencies of 3.82%, 1.30%, and 0.077% for PPy-GR, PANI-GR and PANI, respectively. The incident photon-to-current efficiency (IPCE) of iodine-doped composite-based DSSCs is significantly enhanced.

Structural, thermal and morphological properties of plasma polymerized MnO 2 /PPy composite

Recently, electronically conductive polymers have been studied as the subject of numerous investigations. Among the conductive polymers, which have aromatic ring and heteroatom in the backbone, polypyrrole (PPy) have been of particular interest due to its high electrical conductivity, environmental stability and interesting redox properties associated with the chain heteroatom. In the present work, we report on the MnO2 particles embedded within PPy matrix (MnO2/PPy) as a composite prepared by the rotating plasma polymerization method. Plasma polymerization is used to eliminate disadvantages of other polymerization methods. Plasma polymerization method is cheaper, environmentally friendly and can be prepared for a few seconds with the desired surface properties. Structural properties of composite were ingestigated by using Fourier Transform Infrared Spectroscopy (FTIR) technique. Thermal and morphological properties of composites were examined by Thermogravimetric Analysis (TGA/DTA) and Scanning Electron Microscopy (SEM) techniques, respectively. Results obtained in this research comfirmed the formation of MnO2/PPy composite.

Modification of carbon nanotube with poly(3-hexylthiophene) by using RF rotating plasma

Carbon nanotubes (CNT) is one of the most investigated materials before the invention of graphene.1 Due to its unique properties, CNTs have been used in various applications include sensors, solar cells, transistors, etc.2 However, it makes difficult to make nano-devices based on CNTs at a large scale. For this reason, formation of composite with conducting polymers is a good way for modification of CNT.3 In this study, CNT was modificated with poly(3-hexylthiophene) by using RF rotating plasma. The obtained modified graphene particles were characterized with FTIR, SEM-EDS, XRD and TGA methods.