Search results for "ELECTRONICS"
showing 10 items of 4340 documents
Photoelectrochemical characterization of photocatalysts
2021
Abstract This chapter aims to provide an overview of the photoelectrochemical characterization of semiconducting photocatalysts and, in particular, present Photocurrent Spectroscopy (PCS) as a useful tool in determining the band structure of semiconducting/insulating materials. Some fundamentals on PCS will be provided looking at the experimental setup and underlying its advantages and disadvantages. Then, the photoelectrochemical behavior of a semiconductor/electrolyte junction under irradiation will be presented, also taking into account its crystalline or amorphous nature, highlighting how it is possible to get information on the energetics of the junction. This will be exploited to show…
Direct measurement of optical losses in plasmon-enhanced thin silicon films (Conference Presentation)
2018
Plasmon-enhanced absorption, often considered as a promising solution for efficient light trapping in thin film silicon solar cells, suffers from pronounced optical losses i.e. parasitic absorption, which do not contribute to the obtainable photocurrent. Direct measurements of such losses are therefore essential to optimize the design of plasmonic nanostructures and supporting layers. Importantly, contributions of useful and parasitic absorption cannot be measured separately with commonly used optical spectrophotometry. In this study we apply a novel strategy consisting in a combination of photocurrent and photothermal spectroscopic techniques to experimentally quantify the trade-off betwee…
Photoelectric Current and Dielectric Properties of Barium-Strontium Niobate Ceramics under UV and Visible Irradiation
2015
A study of photocurrent kinetics and dielectric response to infra-low frequencies in the range of the broad phase transition in the Ba0.25Sr0.75Nb2O6 (BSN-75) relaxor ceramics under visible and ultraviolet radiation is reported. Anomalies are revealed in the dependence on field intensity of dielectric permittivity and dielectric loss determined from measurements of polarisation loops before and after illumination. The effects of pyro-electric space charge, polarisation and photovoltaic contributions on behaviour of the measured photocurrent are discussed. Results of the kinetics of photocurrent and dielectric response to infra-low frequency studied at different temperatures are discussed as…
Photoelectrochemical study of passive films on stainless steel in neutral solutions
1991
Abstract Passive films formed on AISI 304 stainless steel in neutral solutions are studied using photoelectrochemical technique. Photocurrents were investigated as a function of the wavelength of the incident light, the electrode potential and the time. The results of the measurements together with capacity measurements indicate that the passive film on AISI 304 shows characteristics of a highly doped amorphous or highly disordered n-type semiconductor. The potential dependence of the optical gap values and of the photocurrent transients can be interpreted assuming that the passive film is an iron-chromium oxide solid solution.
Polymer Halide Perovskites-Waveguides Integrated in Nanocellulose as a Wearable Amplifier-Photodetector System
2018
Semiconductor organometallic halide (CH 3 NH 3 PbX 3 , X=Cl, Br, I) perovskites (MHP) have emerged as a very high promising material for optoelectronics. Their large absorption coefficients, high electronic mobilities, excellent quantum yield of emission at room temperature and tunable band-gap with the composition resulted in a new generation of photovoltaics and electronic devices. In this work, HPVK materials are successfully incorporated on a nanocellulose (NC) substrate with the intention to exploit the interesting properties of HPVK materials to construct wearable devices. In particular, a bilayer Poly(methyl methacrylate) /HPVK deposited on NC resulted in a suitable waveguide to demo…
Photoelectrical Properties of the SBN Relaxor Ceramics in the Range of the Broad Phase Transition
2014
AbstractA study of the effects of white light on photocurrent kinetics and the low and infra-low frequency relaxation of polarization in the barium-strontium niobate SBN‑75 ceramics is reported. It is found that at a low intensity illumination in the range of the relaxor phase the space charge is mainly responsible for manifestation of photo-electrical properties of SBN-75 ceramics.
Electrodes for GaOHPc:PCBM/P3HT:PCBM bulk heterojunction solar cell
2012
Abstract The bulk heterojunction approach appears to be one of the most promising concepts of creating efficient, low cost and easily producible organic solar cells. For this purpose one of the best materials was regioregular poly-3-hexylthiophene (P3HT), which is widely used as a donor molecule and a hole transporter, with soluble fullerene derivative (PCBM) as an acceptor and electron transporter. The main drawback of this highly efficient blend is its limited spectral range, covering only a 350–650 nm spectral interval. So the main aim of the present work was to extend the spectral range of the cell up to 850 nm by adding a second bulk heterojunction layer of complementary absorption spe…
Characterization of Thin Film Cig(S,Se)2 Submodules Using Solar Simulator and Laser Beam Induced Current Techniques
2015
In this work, the electrical and optical characterization of CIG(S,Se)2 sub-modules using both a solar simulator equipment and the Laser Beam Induced Current (LBIC) technique is presented. By using the solar simulator and a proper set-up, the electrical parameters of the modules at varying irradiance and temperatures are determined. In addition, the LBIC measurements are carried out to analyze the 2D photocurrent uniformity of the modules at two different wavelengths. Dispersion values of extracted parameters can be very useful for practically tuning the modelling stage at device/module level.
Photocurrent enhancement in thin a-Si:H solar cells via plasmonic light trapping
2014
Photocurrent enhancement in thin a-Si:H solar cells due to the plasmonic light trapping is investigated, and correlated with the morphology and the optical properties of the selfassembled silver nanoparticles incorporated in the cells' back reflector. © 2014 OSA.
Recent advances in photocurrent spectroscopy of passive films
2003
Abstract The quantitative application of photocurrent spectroscopy (PCS) for the in-situ determination of the composition of passive films and corrosion layers is reviewed in the light of recent theoretical advances, that have allowed to relate the measured optical gaps to the Pauling electronegativities of the film components. The correlations derived are tested versus recent experimental results regarding mixed oxides, anhydrous passive films on metallic alloys and hydroxide layers. The effect of the eventual long-range disorder into the passive film on the optical band gap values is also discussed. New experimental evidence reported for mixed d,d-metal oxides and passive films on sp,d-me…