Search results for "Conductor"
showing 10 items of 1270 documents
Physically-consistent parameterization in the modeling of solar photovoltaic devices
2011
This research tests the standard one-diode model of a crystalline-Si photovoltaic cell, focusing on the physical accuracy. In particular, the (apparent) shunt resistance and the diode ideality factor are studied. Current-voltage characteristics of illuminated crystalline-Si photovoltaic modules are analyzed, and some limits of applicability of the standard model are given. Typical values of the ideality factor for crystalline-Si devices are derived from own experimental data as well as from recently published literature. It is shown that the contribution of the apparent shunt resistance is only significant for cell voltages below about 0.45 V, and depends on irradiance. This result is consi…
Artificial dielectric optical structures: A challenge for nanofabrication
1998
Diffractive optical components can be made using multiple level kinoforms or single level artificial dielectric structures. The latter require the fabrication of pillars of equal depth but differing width and spacing. As a demonstration device, the diffractive optic equivalent of a wedge has been made in GaAs for use at 1.15 μm. The need for all pillars to have the same height was met by using a selective etch and a very thin etch-stop layer on AlGaAs. The experimental diffraction efficiency was 87.8%, among the best ever obtained and close to the theoretical maximum of 97.6%. © 1998 American Vacuum Society.
Scalable Electro-Optic Control of Localized Bistable Switching in Broad-Area VCSELs Using Reconfigurable Funnel Waveguides
2017
We demonstrate a steplike optical modulation based on the activation and deactivation of a bistable localized structure using a photoinduced and reconfigurable miniaturized 30 × 30 μm electroactivated funnel waveguide. Control of a single 10-μm-diameter spot in a 200-μm-diameter vertical-cavity surfaceemitting laser at 980 nm is achieved modulating the phase of an exciting beam in the specific position of the spot in the cavity. This localized on-off response can be scaled into arrays and offer a possible route to fast integrated optical logical functions and memory at low intensities at near-infrared wavelengths.
Simulation of parasitic effects on Silicon Carbide devices for automotive electric traction
2020
Wide Band Gap (WBG) semiconductors are increasingly addressed towards Electric Vehicle (EV) applications, due to their significant advantages in terms of high-voltage and low-losses performances, suitable for high power applications. Nevertheless, the packaging in WBG devices represents a challenge for designers due to the notable impact that inductive and capacitive parasitic components can bring in high switching frequency regime in terms of noise and power losses. In this paper, a comparison between conventional Silicon (Si) and emerging Silicon-Carbide (SiC) power switching devices is presented. The effects of inductive parasitic effects and switching frequency are investigated in simul…
Efficient Monolithic Perovskite/Perovskite Tandem Solar Cells
2016
Thin-film solar cells suffer from various types of recombination, of which leakage current usually dominates at lower voltages. Herein, we demonstrate first a three-order reduction of the shunt loss mechanism in planar methylammonium lead iodide perovskite solar cells by replacing the commonly used hole transport layer poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) with a better hole-selective polyarylamine. As a result, these cells exhibit superior operation under reduced light conditions, which we demonstrate for the extreme case of moonlight irradiance, at which open-circuit voltages of 530 mV can still be obtained. By the shunt removal we also observe the VOC to dro…
Considering lithium-ion battery 3D-printing via thermoplastic material extrusion and polymer powder bed fusion
2021
Abstract In this paper, the ability to 3D print lithium-ion batteries through Pmnbspace thermoplastic material extrusion and polymer powder bed fusion is considered. Focused on the formulation of positive electrodes composed of polypropylene, LiFePO4 as active material, and conductive additives, advantages and drawbacks of both additive manufacturing technologies, are thoroughly discussed from the electrochemical, electrical, morphological and mechanical perspectives. Based on these preliminary results, strategies to further optimize the electrochemical performances are proposed. Through a comprehensive modeling study, the enhanced electrochemical suitability at high current densities of va…
ChemInform Abstract: Electrical Conductive Coordination Polymers
2012
Coordination polymers are currently one of the hottest topics in Inorganic and Supramolecular Chemistry. This critical review summarizes the current state-of-the-art on electrical conductive coordination polymers (CPs), also named metal–organic frameworks (MOFs). The data were collected following two sort criteria of the CPs structure: dimensionality and bridging ligands (151 references).
Molecular Tuning of the Magnetic Response in Organic Semiconductors
2017
The tunability of high-mobility organic semi-conductors (OSCs) holds great promise for molecular spintronics. In this study, we show this extreme variability - and therefore potential tunability - of the molecular gyromagnetic coupling ("g-") tensor with respect to the geometric and electronic structure in a much studied class of OSCs. Composed of a structural theme of phenyl- and chalcogenophene (group XVI element containing, five-membered) rings and alkyl functional groups, this class forms the basis of several intensely studied high-mobility polymers and molecular OSCs. We show how in this class the g-tensor shifts, $\Delta g$, are determined by the effective molecular spin-orbit couplin…
Positrons and electron-irradiation induced defects in the layered semiconductor InSe
1992
The positron annihilation characteristics of the layered semiconductor InSe have been investigated. No evidence for low temperature positron trapping is found in as-grown and heavily deformed InSe. The temperature dependence of the S-parameter in these sample exhibits an increase rate in good agreement with the linear expansion coefficient along the c-axis. The positron lifetime spectra of electron-irradiated 0.01% Sn-doped InSe show a long-lifetime component of 336 ps which is tentatively attributed to positrons trapped at isolated In vacancies. Isochronal annealing experiments performed on these samples show that the recovery of the positron lifetime measured at 77K is accomplished in two…
Modified Donnan phenomena in polyaniline with poly(vinyl sulphonate) chains
1993
We develop a physical model, based on the modified Donnan phenomena ideas introduced previously by the authors, to describe the acid doping of the conducting polymer polyaniline. The theory is motivated by the experimental work of Asturias et al. [Ber. Bunsenges. Phys. Chem. 95, 1381 (1991)]. Good agreement between theory and experiment is found.