Muzaffer Can

Electropolymerization of acetonitrile solutions containing aniline and thiophene

The effect of thiophene on the electropreparation and properties of polyaniline was investigated. The presence of thiophene in solutions of aniline in acetonitrile accelerates the formation and causes an improvement in the conductivity of polyaniline films. A catalytic mechanism related to the role of thiophene cation radicals which involves chemical and electrochemical oxidation steps is proposed. In acidic solutions containing higher thiophene to aniline concentration ratios thiophene enters into the structure of the polymer forming a copolymer. The structure and properties of this novel conducting polymer were elucidated using cyclic voltammetry, GCMS, elemental analysis and DSC methods.

Polyaniline micro-rods based heterojunction solar cell: Structural and photovoltaic properties

The present paper reports the fabrication and photovoltaic characterization of pure and dodecyl benzene sulfonic acid (DBSA)-doped polyaniline (PAni) micro-rods polymer/n-Si heterojunction solar cells, and also the morphological and structural properties of pure and micro-rods PAni doping with DBSA. The device shows a strong photovoltaic behavior with a maximum open-circuit voltage Voc of 0.83 V, a short-circuit current Jsc of 14.72 mA cm−2, fill factor FF of 0.54 resulting in an estimated device efficiency η of 6.13% under simulated solar light with the intensity of 100 mW/cm2. The results indicate that the Au/DBSA-doped PAni micro-rods/n-Si heterojunction structure might be promising for the solar cell applications.

Fabrication and electrical characterization of pyrrole–aniline copolymer-based Schottky diodes

In this work, pyrrole–aniline copolymer/p-Si structure has been fabricated by forming a thin organic copolymer film on a p-Si wafer. A good rectifying behavior was seen from the current–voltage (I–V) characteristics. The characteristic parameters of the structure such as barrier height, ideality factor, interface states density and series resistance were determined from the electrical measurements using I–V, Cheungs, and modified Nordes function. The calculated barrier height values from different methods have shown the consistency of the approaches. The obtained ideality factor which is greater than unity refers to the deviation from ideal diode characteristics. This deviation can be attributed to secondary mechanisms, which include interface dipoles due to interface doping or specific interface structure, as well as fabrication-induced defects at the interface. The energy distribution of interface-state density of the copolymer-based structure was determined, and the interface-state density was found to vary from 1.27 × 1016 cm−2 eV−1 in (0.07 – Ev) eV to 2.45 × 1015 cm−2 eV−1 in (0.52 – Ev) eV. Furthermore, these copolymers were characterized with UV–vis, FTIR techniques, and thermal analysis.

Electropreparation and electrochemical stability of polythiophenes in acetonitrile containing anhydrous HBF4

The electrooxidation behavior of thiophene and 3-methylthiophene on a Pt surface in an acetonitrile + tetrabutylammonium tetrafluoroborate solution were investigated. The electropolymerization of these monomers was studied in neutral, acidic, and basic media. The effects of thiophene concentration and the added acid were elucidated. The polythiophene and poly(3-methylthiophene) films formed were characterized by their cyclic voltammograms in a blank solution and dry conductivities were measured. Electrochemical properties of these polymers in the same medium were investigated in the absence and in the presence of added anhydrous acid and base. The behavior of the freshly prepared films was compared with that which lost its electroactivity as a result of electrooxidation using cyclic voltammetry, controlled potential coulometry, and FTIR spectroscopy. The mechanisms related to the formation of the polymers and their electroactivity loss were proposed.

Theoretical investigation of the proton effect on electropolymerization of aniline

The effect of the protonation on electropolymerization of aniline was elucidated theoretically. It was shown that the proton effects stabilities of p-aminodiphenylamine which is the primary species formed following electrooxidation in acidic media. The position of protonation is elucidated. Geometrical optimizations and calculated energies (strain and total energy and heat of formation) and proton affinity values predict that the p-aminodiphenylamine is preferably protonated on the amine nitrogen between the phenyl rings. It is concluded that the polymer backbone is relaxed and the strained structure is removed upon stepwise protonation during the growth of the polymer.

The effect of the proton on electropolymerization of the thiophene

Abstract Electropolymerization of thiophene was investigated in neutral and acidic medium from the standpoint of film formation and conductivity. Results obtained from voltammetric investigations have shown that proton affects both the electropolymerization of thiophene and its conductivity. This effect was explained by theoretical calculations using molecular mechanic (MM+, MM2) and semi-empirical (AM1) methods. From these calculations, it is seen that proton is significantly important in the stabilization and growth of the polymer. Proton is added to the sulfur atom in the polymer, which has a basic character because of its lone-pair electrons. With the addition of proton, the effect of the lone-pair electrons to the delocalization existing in the ring and the contribution to the conductivity of polythiophene is removed. Thus, the conjugation in the ring is reduced to the π-system in carbon skeleton and the structure of the protonated polythiophene resembles to that of polyacetylene.

The Chemical and Physical Characterizations of Aniline-Co-3-methyl Thiophene Copolymer Synthesized by a New Oxidant

Chemical polymerization of aniline (AN), 3-methyl thiophene (3MT), and AN + 3MT mixture was investigated with periodic acid, H5IO6, which is a new oxidant, in the presence of HBF4. Studies show that the polymer synthesized in the solution containing AN and 3MT is an aniline-co-3-methyl thiophene (AC3MT) copolymer. The copolymer synthesized was characterized with UV-visible (UV-vis), and Fourier transform-infrared spectroscopy (FT-IR) techniques, thermogravimetric techniques (TGA/DTG), DC and AC conducting measurements, and elemental analysis. The aniline-co-3-methyl thiophene copolymers in different combinations were formed depending on the concentration of AN and 3MT used. Properties such as conductivity and thermal stability and combinations of the copolymers were significantly affected by the monomer concentration.