Search results for " Devices"
showing 10 items of 517 documents
Power losses comparison between Silicon Carbide and Silicon devices for an isolated DC-DC converter
2021
In recent years, new efficient power devices have been implemented. Silicon Carbide has replaced silicon as regards the production and the utilization of many devices, such as MOSFETs, diodes, IGBTs and many others. SiC devices are characterized by a low reverse recovery charge, high carrier saturation velocity, by which it is possible to work at high frequency, and high breakdown voltage. Thanks to the great thermal conductivity and the wide bandgap, these devices can operate at high temperature and reach high voltages and currents. What is important to stress is the fact that power losses in SiC devices are lower than the silicon ones. These are the reasons why these devices are utilized …
Polymeric Thin Films for Organic Electronics: Properties and Adaptive Structures
2013
This review deals with the correlation between morphology, structure and performance of organic electronic devices including thin film transistors and solar cells. In particular, we report on solution processed devices going into the role of the 3D supramolecular organization in determining their electronic properties. A selection of case studies from recent literature are reviewed, relying on solution methods for organic thin-film deposition which allow fine control of the supramolecular aggregation of polymers confined at surfaces in nanoscopic layers. A special focus is given to issues exploiting morphological structures stemming from the intrinsic polymeric dynamic adaptation under non-…
Real-time polarimetric optical sensor using macroporous alumina membranes.
2013
We report on the demonstration of real-time refractive index sensing within 60 μm thick free-standing macroporous alumina membranes with pore diameters of 200 nm. The free-standing macroporous alumina membranes allow the analytes to flow through the pores for targeted delivery, resulting in fast sensing responses. The polarimetric measurement platform exploits the optical anisotropy of the membranes in monitoring the refractive index variations of the analytes that fill the pores, providing highly sensitive and real-time measurements. The experimental characterization of the membranes' birefringence at wavelengths of 808, 980, and 1500 nm showed a decrease in birefringence for shorter wavel…
Layered Double Hydroxides in Bioinspired Nanotechnology
2020
Layered Double Hydroxides (LDHs) are a relevant class of inorganic lamellar nanomaterials that have attracted significant interest in life science-related applications, due to their highly controllable synthesis and high biocompatibility. Under a general point of view, this class of materials might have played an important role for the origin of life on planet Earth, given their ability to adsorb and concentrate life-relevant molecules in sea environments. It has been speculated that the organic–mineral interactions could have permitted to organize the adsorbed molecules, leading to an increase in their local concentration and finally to the emergence of life. Inspired by nature, material s…
Long-cavity all-fiber ring laser actively mode locked with an in-fiber bandpass acousto-optic modulator.
2013
We demonstrate low-frequency active mode locking of an erbium-doped all-fiber ring laser. As the mode locker, we used a new in-fiber bandpass acousto-optic modulator showing 74% modulation depth, 3.7 dB power insertion losses, 4.5 nm of optical bandwidth, and 20 dB of nonresonant light suppression. The laser generates 330 ps mode-locked pulses over a 10 ns pedestal, at a 1.538 MHz frequency, with 130 mW of pump power. Fil: Cuadrado Laborde, Christian Ariel. Universidad de Valencia; España. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Centro de Investigaciones Opticas (i); Argentina. Provincia de Buenos Aires. Gobernación. Comisión de In…
Spatiotemporal colorimetry to reveal electrochemical kinetics of poly(o-toluidine) films along ITO surface
2018
Abstract Sheet resistance of transparent conducting electrodes can affect dramatically the electrochromic response of surface confined active species in any electrochromic device. The generated gradient of effective potential on the electrode surface has a direct impact on the electrochemical kinetics of these species. In this work, the electrochromic poly (o-toluidine) (POT) film, a derivative polyaniline, was deposited along a narrow, long transparent indium tin oxide (ITO) supporting electrode with a sheet resistivity of 30 Ω cm−1. This configuration was used as a model to simulate a surface electrical conduction from the external metallic contact to the opposite extreme of ITO with an i…
Correlating the Lifetime and Fluorine Content of Iridium(III) Emitters in Green Light-Emitting Electrochemical Cells
2013
In light-emitting electrochemical cells, the lifetime of the device is intrinsically linked to the stability of the phosphorescent emitter. In this study, we present a series of ionic iridium(III) emitters based on cyclometalating phenylpyridine ligands whose fluorine substituents are varied in terms of position and number. Importantly, despite these structural modifications, the emitters exhibit virtually identical electrochemical and spectroscopic properties, which allows for proper comparison in functional devices. Quantum chemical calculations support the properties measured in solution and suggest great similarities regarding the electronic structures of the emitters. In electrolumines…
Comparison of impact characteristics of four different ice hockey arena dasher boards
2012
During recent years the incidence of ice hockey related concussions has increased. Therefore, the main aim of this study was to determine how dasher board materials and structures affect impact characteristics and thereby concussion risk. The measurements were divided into two parts; 1. physiological characteristics of body checks were determined in real game measurements, and 2. simulation of body checks in the laboratory. Peak forces and stopping distances were determined from the high-speed camera data, and stiffness values were subsequently calculated. Dasher board materials and structures had a clear effect on impact characteristics. Flexible protective shielding material resulted in 1…
Q -switched and modelocked all-fiber lasers based on advanced acousto-optic devices
2011
The interest in all-fiber lasers is stimulated by the inherent advantages they have over bulk lasers in aspects such as heat dissipation and robustness. The performance of Q-switched and modelocked fiber lasers can benefit enormously from the development of all-fiber configurations. A fiber laser with strictly all-fiber components can fulfil the requirements of mechanical stability, low maintenance, enhanced power efficiency, simplified assembly process, and low cost. In this framework, recent developments infiber acousto-optic devices are reviewed that have demonstrated new possibilities for actively Q-switched distributed feedback fiber lasers, modelocking lasers and doubly active Q-switc…
Digital video-electrochemistry (DVEC) to assess electrochromic materials in the frequency domain: RGB colorimetry impedance spectroscopy
2021
Abstract This work is the first one allowing the characterization of electrochromic devices simultaneously at various parts on their surface and different rates of color change. We describe a new proficient and affordable methodology for reporting electrochromic parameters such as coloration efficiency, optical contrast, and switching time based on the use of digital video-electrochemistry (DVEC) in the ac regime, namely RGB colorimetry impedance spectroscopy. Simultaneously with the electrochemical impedance spectroscopy, the RGB color changes of an electrochromic electrode were recorded by a CCD digital camera at 120 digital images per second. In such conditions, RGB electrochromic change…