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ABSTRACT An original polythiophene derivative was characterized to develop the optoelectronic properties of sulfur-containing π-conjugated polymer. The optical properties of the polymer were investigated by UV–visible absorption... more
ABSTRACT An original polythiophene derivative was characterized to develop the optoelectronic properties of sulfur-containing π-conjugated polymer. The optical properties of the polymer were investigated by UV–visible absorption spectroscopy and atomic force microscopy. Investigations of the electrical characteristics of polymer diodes are reported. We present current–voltage characteristics and impedance spectroscopy measurements performed on partially sulfur-containing thin films in sandwich structure ITO/sulfur-containing polymer/Al. The conduction mechanisms in these layers are identified to be a space-charge-limited current. The AC electrical transport of the sulfur-containing polymer is studied as a function of frequency (100 Hz–10 MHz) and temperature in impedance spectroscopy analyses. We interpreted Cole–Cole plots in terms of the equivalent circuit model as a single parallel resistance and a capacitance network in series with a relatively small resistance. The evolution of the electrical parameters deduced from fitting of the experimental data is discussed.
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The large interfacial area of the porous silicon is used as ion sensitive membrane support. The porous layer is oxidized by Rapid Thermal Oxidation (RTO) technique and a calix(4)arene layer was evaporated under vacuum. The structure is... more
The large interfacial area of the porous silicon is used as ion sensitive membrane support. The porous layer is oxidized by Rapid Thermal Oxidation (RTO) technique and a calix(4)arene layer was evaporated under vacuum. The structure is then used as the working electrode of an electrochemical cell and sensor properties were investigated by capacitance measurements. We observed an over-Nernstian response
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Cylodextrin (CD)–polysiloxane gel matrices are used to functionalize EIS (Electrolyte Insulator Semiconductor structure) and ISFET (Ion-Sensitive Field Transistor) devices. Electrochemical measurements were made to study the sensitivity... more
Cylodextrin (CD)–polysiloxane gel matrices are used to functionalize EIS (Electrolyte Insulator Semiconductor structure) and ISFET (Ion-Sensitive Field Transistor) devices. Electrochemical measurements were made to study the sensitivity and the selectivity of this sensitive membrane towards heavy metal ions. For both structures, a Nernstian response and good detection limit of an αCD gel membrane towards Cd2+ ion and for a βCD
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Conducting organic materials offer a unique combination of interesting properties that make them more attractive than inorganic materials currently used in microelectronics. It is advantageous to use organic thin film transistors (OTFT)... more
Conducting organic materials offer a unique combination of interesting properties that make them more attractive than inorganic materials currently used in microelectronics. It is advantageous to use organic thin film transistors (OTFT) when large display areas are required. This needs the enhancement of transistor performances by increasing the Ion/Ioff ratio and the field effect mobility. In this report, the effects
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Electrical measurements have been performed on spin-coated azo-calix[4]arene derivative on pre-cleaned indium thin oxide (ITO) substrates using current versus voltage, capacitance versus voltage and impedance spectroscopy measurements.... more
Electrical measurements have been performed on spin-coated azo-calix[4]arene derivative on pre-cleaned indium thin oxide (ITO) substrates using current versus voltage, capacitance versus voltage and impedance spectroscopy measurements. The nature of trap states in single layer ITO/azo-calix[4]arene derivative/Al organic diodes has also been investigated. The energy band gap of the thin film containing calixarene derivative has been measured by UV–Vis absorption
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Large size odd-numbered calixarenes were used for the first time as ionophoric agents for the functionalization of ISFET microsensors and EIS structures through thermal evaporation process. Both calixarenes have shown a nernstian... more
Large size odd-numbered calixarenes were used for the first time as ionophoric agents for the functionalization of ISFET microsensors and EIS structures through thermal evaporation process. Both calixarenes have shown a nernstian sensitivity over three decades towards only copper (II) activities. Very low selectivity coefficients were observed for K+ and Ca2+ whereas Cd2+ and Pb2+ (less than 10−3) can be
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Thin calix[4]arene and calix[6]arene films were deposited using the technique of thermal evaporation under vacuum to fabricate chemical ion-selective field effect transistor (ISFET) microsensors. A high-performance liquid-phase... more
Thin calix[4]arene and calix[6]arene films were deposited using the technique of thermal evaporation under vacuum to fabricate chemical ion-selective field effect transistor (ISFET) microsensors. A high-performance liquid-phase chromatography (HPLC) method was used to verify the non-degradation of the calixarene layers, after the evaporation process. The sensing properties of these ionophores towards alkaline and heavy metal ions were tested. Both devices
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Indium tin oxide (ITO) substrates have been functionalized by several substituted calix[n]arene (n = 5 or 9) derivatives using spin coating to fabricate organic diode devices. The effect of rim size and side substituents has been... more
Indium tin oxide (ITO) substrates have been functionalized by several substituted calix[n]arene (n = 5 or 9) derivatives using spin coating to fabricate organic diode devices. The effect of rim size and side substituents has been investigated by UV–visible absorption spectrophotometry. The energy band gaps of these calixarene derivative thin films have been found in the 1.166–1.450 eV range. The
Research Interests: Engineering, Materials Engineering, Condensed Matter Physics, Atomic Force Microscopy, Impedance Spectroscopy, and 15 moreHigh Frequency, Scanning tunneling microscopy, Thin Film, Physical sciences, Quantum Efficiency, Activation Energy, Band Gap, Optical Properties, Dielectric Relaxation, CHEMICAL SCIENCES, Electrical Properties, Experimental Data, Indium tin oxide, Chemical Structure, and Low voltage
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... Thin Solid Films, 258 (1995), p. 279. [10] M. Bouvet, G. Guillaud, A. Leroy, A. Maillard, S. Spirkovitch and F.-G. Tournilhac. Sens. Actuators, B, Chem., 73 (2001), p. 63. [11] A. Schütze, N. Pieper and J. Zacheja. Sens. Actuators, B,... more
... Thin Solid Films, 258 (1995), p. 279. [10] M. Bouvet, G. Guillaud, A. Leroy, A. Maillard, S. Spirkovitch and F.-G. Tournilhac. Sens. Actuators, B, Chem., 73 (2001), p. 63. [11] A. Schütze, N. Pieper and J. Zacheja. Sens. Actuators, B, Chem., 23 (1995), p. 215. ...
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The influence of film morphology on the electrical behaviour of an MEH-PPV/C60 organic solar cells has been investigated. The dissociation of photogenerated charge pairs in composites of buckminsterfullerenes (C60) in a conjugated polymer... more
The influence of film morphology on the electrical behaviour of an MEH-PPV/C60 organic solar cells has been investigated. The dissociation of photogenerated charge pairs in composites of buckminsterfullerenes (C60) in a conjugated polymer matrix (MEH-PPV) forming dispersed heterojunctions was studied at low C60 acceptor concentrations to separate electron transfer from charge transport effects. The motivation of this study was to
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A studies of a tetrakis(phenylazo)calix[4]arene derivative have been developed for cation recognition. The complexation properties of this ligand towards transition metal ions have been investigated by UV–Visible and fluorescence... more
A studies of a tetrakis(phenylazo)calix[4]arene derivative have been developed for cation recognition. The complexation properties of this ligand towards transition metal ions have been investigated by UV–Visible and fluorescence spectroscopies. It has been found that the ligand has remarkable complexation ability for transition metal Ni2+, Co2+, Hg2+, heavy metal ions Al3+ and Pb2+ with an exceptional high affinity for the
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New large size calixarenes have been synthesized and tested as ionophores. The applications of these new even-membered macrocycles in the field of chemical sensors have been studied. Thin p-tert-butyl calix[10 and 12]arenes film were... more
New large size calixarenes have been synthesized and tested as ionophores. The applications of these new even-membered macrocycles in the field of chemical sensors have been studied. Thin p-tert-butyl calix[10 and 12]arenes film were deposited using the technique of thermal evaporation under vacuum on ISFET (Ion Sensitive Field Effect Transistor) and EIS structures (Electrolyte Insulator Semiconductor) surfaces. It was verified
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The anodic etching of n+-type GaAs (100) substrate in HCl aqueous solution has been investigated experimentally using an in situ current–voltage J (V) and capacitance–voltage C (V) measurements. In situ current–voltage, J (V),... more
The anodic etching of n+-type GaAs (100) substrate in HCl aqueous solution has been investigated experimentally using an in situ current–voltage J (V) and capacitance–voltage C (V) measurements. In situ current–voltage, J (V), characteristics of the n+-GaAs/HCl interface exhibit the presence of three potential regions, which are attributed to different reaction mechanisms between HCl and n+-type GaAs surface. Also, current