Search results for "optoelectronic"

Hybrids composites of NCCO/PEDOT for thermoelectric applications

2017

Abstract Organic materials are becoming a realistic roadway to fabricate efficient thermoelectric devices using environmental friendly materials. Such requirements are actually fulfilled by thermoelectric generators operating by conducting polymers, but also by hybrid materials. The combination of organic + inorganic compounds may exhibit a high electrical conductivity and Seebeck coefficient as well as lower thermal conductivity in order to efficiently generate thermoelectric power. In these hybrid compounds, perovskite-type oxides are a suitable election for the inorganic part since they have a high Seebeck coefficient although their electrical conductivity is usually low. Blending them w…

Influence of device geometry on sensor characteristics of planar organic electrochemical transistors.

2009

The response of PEDOT:PSS planar electrochemical transistors to H2O2 can be tuned by varying the ratio between the areas of the channel and the gate electrode. Devices with small gates show lower background signal and higher sensitivity. The detection range, on the other hand, is found to be rather independent of the gate/channel area ratio.

Reduced efficiency roll-off in light-emitting diodes enabled by quantum dot–conducting polymer nanohybrids

2014

We demonstrate QLEDs implementing wider active layers (50 nm) based on QD–conducting polymer nanohybrids, which exhibit a stable operational device performance across a wide range of current densities and brightness. A comparative study reveals that the significant suppression of efficiency roll-off in the high current density regime is primarily attributed to a sufficient charge carrier distribution over the wider active layer and improved charge carrier balance within QDs enabled by the hybridization of QDs with conducting polymers. Utilization of this finding in future studies should greatly facilitate the development of high performance, stable QLEDs at high current density or luminance…

Tailored conjugated polymer Langmuir-Schafer thin films in sensing transistors

2004

Organic Thin Film Transistors (OTFTs) have been fabricated, in a standard bottom gate configuration, with Langmuir-Schäfer (LS) or cast thin films of regioregular poly[1,4-(2,5-dioctyloxyphenylene)-2,5-thiophene], synthesized via an organometallic protocol, as active layers. The transistors electrical characterization has evidenced that LS based devices exhibit better performance level than cast film ones. Appealing perspectives for newly substituted conjugated polymers in OTFT sensing devices are discussed.

Thermal sensor based on a polymer nanofilm

2016

In this work, we have developed a thermal sensor based on poly(3,4 ethylenedioxythiophene) (PEDOT) nanofilms as thermoelectric material. The PEDOT nanofilms have been synthesized by the electrochemical polymerization method. The thicknesses of the films were around 120 nm. The doping level of PEDOT was controlled by chemical reduction using hydrazine. The achieved Seebeck coeficient is 40 uV/K. A PEDOT nanofilm was integrated into an electronic circuit that amplifies the voltage originated from the Seebeck effect. The temperature increment produced by a fingerprint touching the film is enough to switch on a light emitting diode. Peer Reviewed

Environment assisted photoconversion of luminescent surface defects in SiO 2 nanoparticles

2017

Abstract Time-resolved photoluminescence investigation on SiO 2 nanoparticles was carried out in controlled atmosphere, with the aim to discern the effects induced on the typical blue luminescence band by high power UV Nd:YAG laser photons (4.66 eV) and by some selected molecular species of the air (O 2 , N 2 , CO 2 , H 2 O). These factors ultimately determine both the brightness and photostability of the emitting defect, so as to limit the unique and attracting potentialities offered by this system in many applicative fields. Here it is highlighted that the effects due to photons and molecules, singularly considered, are not additive, the radiation being more dramatic in reducing the emiss…

Probing of nanocontacts inside a transmission electron microscope

2007

In the past twenty years, powerful tools such as atomic force microscopy have made it possible to accurately investigate the phenomena of friction and wear, down to the nanometer scale. Readers of this book will become familiar with the concepts and techniques of nanotribology, explained by an international team of scientists and engineers, actively involved and with long experience in this field. Edited by two pioneers in the field, 'Fundamentals of Frictions and Wear at the Nanoscale' is suitable both as first introduction to this fascinating subject, and also as a reference for researchers wishing to improve their knowledge of nanotribology and to keep up with the latest results in this …

Dopant Contrast in Semiconductors as Interpretation Challenge at Imaging by Electrons

2007

Mechanisms responsible for the contrast between differently doped areas in semiconductors, which is observed in electron micrographs, is discussed as regards the key factors determining the sign and magnitude of the contrast. Experimental data obtained by means of the scanning electron microscope (SEM), scanning low energy electron microscope and photoelectron emission microscope are reviewed together with hints following from them for compilation of a model of the contrast mechanism.

1996

The uses of atomic force microscopy, scanning tunneling microscopy, electron spectroscopic imaging, electron energy loss spectroscopy and low voltage, high resolution scanning electron microscopy in polymer research are reviewed

Electro-optic dynamics in thermally poled Ge core doped silica fibre

2003

The electro-optic (EO) dynamics of a twin hole germania core doped fibre when an applied electric field at elevated temperature modifies the symmetry of glass is reported. An EO peak was recorded after 10 min poling. The results were interpreted with a two-space charge model.