The present study investigates the effects of Lewis acid and protonic acid on the chemical polyme... more The present study investigates the effects of Lewis acid and protonic acid on the chemical polymerization of indole using electrical conductivity measurements and nuclear magnetic resonance, UV–visible, and Fourier transform infrared spectroscopy techniques. These effects are explained by theoretical calculations on the basis of molecular mechanic (MM+) and semi-empirical Austin Model 1 methods. As a result, it has been shown
The effect of thiophene on the electropreparation and properties of polyaniline was investigated.... more 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.
We have formed conjugated polymeric aniline-thiophene organic material on p-Si substrate by addin... more We have formed conjugated polymeric aniline-thiophene organic material on p-Si substrate by adding polyaniline-poly-3-methyl thiophene blend solution in acetonitrile on top of a p-Si substrate and then evaporating the solvent. It has been seen that the forward bias current-voltage (I-V) characteristics of polyaniline-poly-3-methyl thiophene blend/p-Si/Al with a barrier height value of 0.60 eV and an ideality factor value of 3.37 showed rectifying behaviour at room temperature. The polyaniline-poly-3-methyl thiophene blend/p-Si/Al Schottky barrier diode showed non-ideal I-V behaviour with the value of ideality factor greater than unity that could be ascribed to the interfacial layer, interface states and series resistance. Furthermore, Cheung's functions and modified Norde's function were used to extract the diode parameters including ideality factor, barrier height and series resistance. It has been seen that there is a good agreement between the barrier height values from all methods. However, the values of series resistance obtained from Cheung's functions is higher than the values obtained from Norde's functions. The energy distribution of interface states density, determined from forward bias current-voltage (I-V) characteristic technique at room temperature, increases exponentially with bias from 2.81 Â 10 16 cm À2 eV À1 in (0.73-E v) eV to 1.14 Â 10 17 cm À2 eV À1 in (0.48-E v) eV.
We have fabricated a poly(aniline-3-methyl thiophene) organic thin material on p-Si substrate by ... more We have fabricated a poly(aniline-3-methyl thiophene) organic thin material on p-Si substrate by placing a solution of copolymer in acetonitrile on top of a p-Si substrate and then evaporating the solvent. The electrical and interface state density properties of the poly(aniline-3-methyl thiophene) copolymer/p-Si/Al diode have been investigated through methods using current-voltage (I-V), Cheung's, and a modified Norde's function. Good agreement was observed with the values of barrier height as obtained from all of these methods. The diode shows a non-ideal I-V behavior with an ideality factor greater than unity, which could be ascribed to the interfacial layer, interface states and series resistance. The interface state density of diode was determined using the forward-bias I-V characteristic technique at room temperature, and it decreases exponentially with bias from 1.39 × 10 16 cm −2 eV −1 in (0.06 − E v) eV to 4.86 × 10 15 cm −2 eV −1 in (0.51 − E v) eV.
The chemical polymerization of aniline in anhydrous medium was investigated using periodic acid, ... more The chemical polymerization of aniline in anhydrous medium was investigated using periodic acid, H 5 IO 6 as an oxidant. This is the first time that H 5 IO 6 has been used as an oxidant in the chemical synthesis of conductive polymers. The product was characterized by FTIR, UV-vis spectroscopies, scanning electron microscope (SEM), energy dispersive X-ray (EDX) spectroscopy, thermogravimetric (TG) analysis, and electrical conductivity measurements. EDX and thermogravimetric analysis showed that Pani includes ClO 4 − and iodine or iodide ion as dopants. Electrical conductivity of polyaniline with H 5 IO 6 was measured as 100 S cm −1. H 5 IO 6 oxidant produces first IO 3 − and then I 2. Therefore, it could ensure both oxidation of aniline by IO 3 − and then doping polyaniline with I 2 , without any residual oxidant contamination. I 2 , which is a well known extrinsic dopant, was produced intrinsically in this study. Thus, H 5 IO 6 was found to be an effective oxidant material for the chemical polymerization of aniline.
The effect of the protonation on electropolymerization of aniline was elucidated theoretically. I... more 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.
Protonation and oligomerization mechanisms of pyrrole monomer were elucidated in the presence of ... more Protonation and oligomerization mechanisms of pyrrole monomer were elucidated in the presence of acid such as HBF 4 and Lewis acid such as AlCl 3 , FeCl 3 in acetonitrile solutions, using experimental methods such as UV-vis and AA spectroscopy and semi-empirical AM1 calculations. It was observed that pyrrole interacts with proton and Lewis acids on similar mechanisms to produce pyrrole oligomers. The theoretical studies predicted that the both types of acids add to the pyrrole ring on C b atom. These studies also showed that FeCl 3 , which is used as oxidative agent in the chemical polymerizations, adds to the polypyrrole chain as well.
The present study investigates the effects of Lewis acid and protonic acid on the chemical polyme... more The present study investigates the effects of Lewis acid and protonic acid on the chemical polymerization of indole using electrical conductivity measurements and nuclear magnetic resonance, UV–visible, and Fourier transform infrared spectroscopy techniques. These effects are explained by theoretical calculations on the basis of molecular mechanic (MM+) and semi-empirical Austin Model 1 methods. As a result, it has been shown
The effect of thiophene on the electropreparation and properties of polyaniline was investigated.... more 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.
We have formed conjugated polymeric aniline-thiophene organic material on p-Si substrate by addin... more We have formed conjugated polymeric aniline-thiophene organic material on p-Si substrate by adding polyaniline-poly-3-methyl thiophene blend solution in acetonitrile on top of a p-Si substrate and then evaporating the solvent. It has been seen that the forward bias current-voltage (I-V) characteristics of polyaniline-poly-3-methyl thiophene blend/p-Si/Al with a barrier height value of 0.60 eV and an ideality factor value of 3.37 showed rectifying behaviour at room temperature. The polyaniline-poly-3-methyl thiophene blend/p-Si/Al Schottky barrier diode showed non-ideal I-V behaviour with the value of ideality factor greater than unity that could be ascribed to the interfacial layer, interface states and series resistance. Furthermore, Cheung's functions and modified Norde's function were used to extract the diode parameters including ideality factor, barrier height and series resistance. It has been seen that there is a good agreement between the barrier height values from all methods. However, the values of series resistance obtained from Cheung's functions is higher than the values obtained from Norde's functions. The energy distribution of interface states density, determined from forward bias current-voltage (I-V) characteristic technique at room temperature, increases exponentially with bias from 2.81 Â 10 16 cm À2 eV À1 in (0.73-E v) eV to 1.14 Â 10 17 cm À2 eV À1 in (0.48-E v) eV.
We have fabricated a poly(aniline-3-methyl thiophene) organic thin material on p-Si substrate by ... more We have fabricated a poly(aniline-3-methyl thiophene) organic thin material on p-Si substrate by placing a solution of copolymer in acetonitrile on top of a p-Si substrate and then evaporating the solvent. The electrical and interface state density properties of the poly(aniline-3-methyl thiophene) copolymer/p-Si/Al diode have been investigated through methods using current-voltage (I-V), Cheung's, and a modified Norde's function. Good agreement was observed with the values of barrier height as obtained from all of these methods. The diode shows a non-ideal I-V behavior with an ideality factor greater than unity, which could be ascribed to the interfacial layer, interface states and series resistance. The interface state density of diode was determined using the forward-bias I-V characteristic technique at room temperature, and it decreases exponentially with bias from 1.39 × 10 16 cm −2 eV −1 in (0.06 − E v) eV to 4.86 × 10 15 cm −2 eV −1 in (0.51 − E v) eV.
The chemical polymerization of aniline in anhydrous medium was investigated using periodic acid, ... more The chemical polymerization of aniline in anhydrous medium was investigated using periodic acid, H 5 IO 6 as an oxidant. This is the first time that H 5 IO 6 has been used as an oxidant in the chemical synthesis of conductive polymers. The product was characterized by FTIR, UV-vis spectroscopies, scanning electron microscope (SEM), energy dispersive X-ray (EDX) spectroscopy, thermogravimetric (TG) analysis, and electrical conductivity measurements. EDX and thermogravimetric analysis showed that Pani includes ClO 4 − and iodine or iodide ion as dopants. Electrical conductivity of polyaniline with H 5 IO 6 was measured as 100 S cm −1. H 5 IO 6 oxidant produces first IO 3 − and then I 2. Therefore, it could ensure both oxidation of aniline by IO 3 − and then doping polyaniline with I 2 , without any residual oxidant contamination. I 2 , which is a well known extrinsic dopant, was produced intrinsically in this study. Thus, H 5 IO 6 was found to be an effective oxidant material for the chemical polymerization of aniline.
The effect of the protonation on electropolymerization of aniline was elucidated theoretically. I... more 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.
Protonation and oligomerization mechanisms of pyrrole monomer were elucidated in the presence of ... more Protonation and oligomerization mechanisms of pyrrole monomer were elucidated in the presence of acid such as HBF 4 and Lewis acid such as AlCl 3 , FeCl 3 in acetonitrile solutions, using experimental methods such as UV-vis and AA spectroscopy and semi-empirical AM1 calculations. It was observed that pyrrole interacts with proton and Lewis acids on similar mechanisms to produce pyrrole oligomers. The theoretical studies predicted that the both types of acids add to the pyrrole ring on C b atom. These studies also showed that FeCl 3 , which is used as oxidative agent in the chemical polymerizations, adds to the polypyrrole chain as well.
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