ABSTRACT An original polythiophene derivative was characterized to develop the optoelectronic pro... 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.
We have synthesized two poly(p-phenylene vinylene) (PPV) derivatives. The first one consists of a... more We have synthesized two poly(p-phenylene vinylene) (PPV) derivatives. The first one consists of a copolymer formed by a random succession of phenylene vinylene and ether groups and the second one is characterized by a pendant side chain containing ether groups hereafter referred to as polyXI and C8-PPV respectively. The polymer’s chemical structures were characterized by 13C solid state NMR, FTIR
The large interfacial area of the porous silicon is used as ion sensitive membrane support. The p... 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
Cylodextrin (CD)–polysiloxane gel matrices are used to functionalize EIS (Electrolyte Insulator S... 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
Conducting organic materials offer a unique combination of interesting properties that make them ... 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
Two new anthracene-core conjugated molecules, 1-(9-anthrylvinyl)-4-benzyloxybenzene (AVB) and 1,4... more Two new anthracene-core conjugated molecules, 1-(9-anthrylvinyl)-4-benzyloxybenzene (AVB) and 1,4-bis(9-anthrylvinyl)benzene (AV2B), were synthesized by the Wittig reaction. Organic thin films based on these derivatives were elaborated using thermal evaporation under high vacuum. The UV–vis film spectra show an anthracene-type absorption behavior for the two π-conjugated systems with an optical gap of 2.77eV for AVB and 2.55eV for AV2B. These derivatives reveal
Electrical measurements have been performed on spin-coated azo-calix[4]arene derivative on pre-cl... 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
Large size odd-numbered calixarenes were used for the first time as ionophoric agents for the fun... 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
Thin calix[4]arene and calix[6]arene films were deposited using the technique of thermal evaporat... 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
Indium tin oxide (ITO) substrates have been functionalized by several substituted calix[n]arene (... 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
ABSTRACT An original polythiophene derivative was characterized to develop the optoelectronic pro... 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.
We have synthesized two poly(p-phenylene vinylene) (PPV) derivatives. The first one consists of a... more We have synthesized two poly(p-phenylene vinylene) (PPV) derivatives. The first one consists of a copolymer formed by a random succession of phenylene vinylene and ether groups and the second one is characterized by a pendant side chain containing ether groups hereafter referred to as polyXI and C8-PPV respectively. The polymer’s chemical structures were characterized by 13C solid state NMR, FTIR
The large interfacial area of the porous silicon is used as ion sensitive membrane support. The p... 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
Cylodextrin (CD)–polysiloxane gel matrices are used to functionalize EIS (Electrolyte Insulator S... 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
Conducting organic materials offer a unique combination of interesting properties that make them ... 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
Two new anthracene-core conjugated molecules, 1-(9-anthrylvinyl)-4-benzyloxybenzene (AVB) and 1,4... more Two new anthracene-core conjugated molecules, 1-(9-anthrylvinyl)-4-benzyloxybenzene (AVB) and 1,4-bis(9-anthrylvinyl)benzene (AV2B), were synthesized by the Wittig reaction. Organic thin films based on these derivatives were elaborated using thermal evaporation under high vacuum. The UV–vis film spectra show an anthracene-type absorption behavior for the two π-conjugated systems with an optical gap of 2.77eV for AVB and 2.55eV for AV2B. These derivatives reveal
Electrical measurements have been performed on spin-coated azo-calix[4]arene derivative on pre-cl... 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
Large size odd-numbered calixarenes were used for the first time as ionophoric agents for the fun... 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
Thin calix[4]arene and calix[6]arene films were deposited using the technique of thermal evaporat... 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
Indium tin oxide (ITO) substrates have been functionalized by several substituted calix[n]arene (... 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
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