Electrodeposition and Photo-electrochemical behaviour of CIGS Thin Films and Nanowires arrays for Solar Cell

Ultrafast lead-acid battery with nanostructured Pb and PbO2 electrodes

Lead-acid batteries (LABs) are still extensively used in the field of energy storage, owing to a well-known and reliable technology. LABs can deliver high power and store energy for a very long time. In addition, they are reliable and easy to produce. The raw materials for their manufacture are practically unlimited, and about 95% of the materials can be recovered and reused. However, the lower specific energy storage (about 30-40 Wh kg-1), in comparison with other storage systems, limits their use in the most emerging and challenging applications, like electrical mobility, due to the high atomic weight of lead [1]. One of the principal limitations in the use of LABs in electric vehicles (E…

Ultraviolet quasi-phase-matched second harmonic generation in surface periodically poled lithium niobate optical waveguides

The compatibility of low concentration (alpha-phase) proton exchange channel waveguides with electric field surface periodic poling of congruent lithium niobate (SPPLN) crystals has been experimentally demonstrated. With such waveguides, we obtained ultraviolet second harmonic generation (SHG) by first order quasi-phase-matching (QPM), a result made possible by the fabrication, on Z-cut LN crystals, of periodic structures with a pitch down to 750 nm. Nonlinear copropagating QPM-SHG measurements have been carried out on such structures. The pump source was a Ti:sapphire laser with a tunability range of 700-980 nm and a 40 GHz linewidth. We have measured UV continuous wave light at 390 nm by …

Random quasi-phase-matched second-harmonic generation in periodically poled lithium tantalate

We observe second harmonic generation via random quasi-phase-matching in a 2.0 micron periodically poled, 1-cm-long, z-cut lithium tantalate. Away from resonance, the harmonic output profiles exhibit a characteristic pattern stemming from a stochastic domain distribution and a quadratic growth with the fundamental excitation, as well as a broadband spectral response. The results are in good agreement with a simple model and numerical simulations in the undepleted regime, assuming an anisotropic spread of the random nonlinear component. (C) 2010 Optical Society of America

Anisotropic Electron Kinetics and Distribution Functions in High Intensity Laser-Plasma Interactions

Plasma Electron Kinetics and Distribution Functions in Laser Fields

A concise review of the properties of electron distribution functions in a fully ionized plasma in the presence of a high-frequency laser field is presented. In detail is discussed the physical origin of most of the reported results in the case of strong fields. The presence of a laser field, through the inverse bremsstrahlung absorption, alters dynamically the roles of and the interplay between electron-ion and electron-electron collisions shaping the distribution function. Special attention is paid to the role of e-e collisions in the process of laser-plasma interaction.

Surface periodic poling in congruent lithium tantalate

CulnSe2/Zn(S,O,OH) junction on Mo foil by electrochemical and chemical route for photovoltaic applications

Electrodeposition is a convenient technique for the development of low cost materials for photovoltaic (PV) device processing. Using a single step electrodeposition route, several groups have fabricated CIS (CuInSe) and CIGS (CuInGaSe) films [1]. One of the most important requirements for successful application of one-step electrodeposition film formation, is the ability to control composition of the deposited films and to develop polycrystalline microstructures with a low surface roughness and high sintered density. In this preliminary work, CIS films were produced by single bath electrodeposition finding the optimal conditions in order to achieve a dense film with high crystallinity and u…

GENERAZIONE DI SECONDA ARMONICA MEDIANTE RANDOM QUASI-PHASE-MATCHING IN TANTALATO DI LITIO POLATO PERIODICAMENTE

We experimentally observed and explained bulk Second Harmonic Generation via Random Quasi-Phase-Matching, derived from a periodically poled Lithium Tantalate sample with a randomly patterned mark-to-space-ratio.

UV Generation in lithium niobate proton exchanged optical waveguides

University of Palermo: Exploiting the Optical Quadratic Nonlinearity of Zinc-Blende Semiconductors for Guided-Wave Terahertz Generation: A Material Comparison

Content synopsis of the following paper: Matteo Cherchi, Alberto Taormina, Alessandro C. Busacca, Roberto L. Oliveri, Saverio Bivona, Alfonso C. Cino, Salvatore Stivala, Stefano Riva Sanseverino, and Claudio Leone, "Exploiting the Optical Quadratic Nonlinearity of Zinc-Blende Semiconductors for Guided-Wave Terahertz Generation: A Material Comparison", IEEE Journal of Quantum Electronics, Vol. 46, N. 3, March 2010

High-Performance Lead-Acid Batteries Enabled by Pb and PbO2 Nanostructured Electrodes: Effect of Operating Temperature

Lead-acid batteries are now widely used for energy storage, as result of an established and reliable technology. In the last decade, several studies have been carried out to improve the performance of this type of batteries, with the main objective to replace the conventional plates with innovative electrodes with improved stability, increased capacity and a larger active surface. Such studies ultimately aim to improve the kinetics of electrochemical conversion reactions at the electrode-solution interface and to guarantee a good electrical continuity during the repeated charge/discharge cycles. To achieve these objectives, our contribution focuses on the employment of nanostructured electr…

Nanostructured Electrochemical Devices for Sensing, Energy Conversion and Storage

Nanomaterials are very promising to enhance device performances for sensing, sustainable energy production, and energy conversion and storage, as extensively reported in the literature [1-3]. In this field, one of the most severe challenge is to find suitable methods for fabricating nanomaterials. Over the years, numerous preparation methods were proposed in the literature, but not all of them are easily scalable and economically advantageous for industrial application. In this context, electrochemical deposition in template is a facile method for fabricating either two- or one-dimensional nanostructured materials because it allows to easily adjust the fundamental parameters controlling the…

Nanostructured lead acid battery for electric vehicles applications

This paper presents an innovative lead acid battery, based on nanostructured active materials. Both charging time and specific energy are greatly enhanced in comparison with commercial lead acid battery. Starting from the extremely valuable performances of the nanostructured battery, also a circuital model, for application in electric vehicle traction, has been specifically developed. The circuital model has demonstrated that an enhanced nanostructured battery allows an increase of traveled distance by electric vehicles.

Generazione di Seconda Armonica per Quasi-Phase-Matching Random in Tantalato di Litio con Poling Periodico

We experimentally observed and explained bulk Second Harmonic Generation via Random Quasi-Phase-Matching, derived from a periodically poled Lithium Tantalate sample with a randomly patterned mark-to-space-ratio.

UV Generation in Surface Periodically Poled Lithium nimbate Proton Exchanged Optical Waveguides

The role of nonlinear optical absorption in narrowband difference-frequency terahertz-wave generation

We present a general analysis of the influence of nonlinear optical absorption on terahertz generation via optical difference frequency generation, when reaching for the quantum conversion efficiency limit. By casting the equations governing the process in a suitably normalized form, including either two-photon- or three-photon-absorption terms, we have been able to plot universal charts for phase matched optical-to-terahertz conversion for different values of the nonlinear absorption coefficients. We apply our analysis to some experiments reported to date, in order to understand to what extent multiphoton absorption could have played a role and also to predict the maximum achievable conver…

Universal charts for optical difference frequency generation in the terahertz domain

We present a universal and rigorous approach to study difference frequency generation in the terahertz domain, keeping the number of degrees of freedom to a minimum, through the definition of a suitable figure of merit. The proposed method relies on suitably normalized charts, that enable to predict the optical-to-terahertz conversion efficiency of any system based on wave propagation in quadratic nonlinear materials. The predictions of our approach are found to be in good agreement with the best experimental results reported to date, enabling also to estimate the d22 nonlinear coefficient of high quality GaSe.

Ultraviolet quasi-phase-matched second harmonic generation in surface periodically poled Lithium Niobate optical waveguides

Continuous-wave backward frequency doubling in periodically poled lithium niobate

We report on backward second-harmonic-generation in bulk periodically poled congruent lithium niobate with a 3.2 microns period. A tunable continuous-wave Ti:sapphire laser allowed us exciting two resonant quasi-phase-matching orders in the backward configuration. The resonances were also resolved by temperature tuning and interpolated with standard theory to extract relevant information on the sample.

EFFECT OF ANNEALING PROCESS ON CIGS FILMS PREPARED BY ONE-STEP ELECTRODEPOSITION

High resolution x-ray investigation of periodically poled lithium tantalate crystals with short periodicity

Domain engineering technology in lithium tantalate is a well studied approach for nonlinear optical applications. However, for several cases of interest, the realization of short period structures (< 2 ��m) is required, which make their characterization difficult with standard techniques. In this work, we show that high resolution x-ray diffraction is a convenient approach for the characterization of such structures, allowing us to obtain in a nondestructive fashion information such as the average domain period, the domain wall inclination, and the overall structure quality.

Electrodeposition and Photoelectrochemical Behaviour of CIGS Thin Films and Nanowire Arrays for Solar Cells

Template electrodeposition and characterization of nanostructured Pb as a negative electrode for lead-acid battery

Abstract Despite Lead Acid Battery (LAB) is the oldest electrochemical energy storage system, diffusion in the emerging sectors of technological interest is inhibited by its drawbacks. The principal ones are low energy density and negative plate sulphating on high rate discharging. In this work, it is shown the possibility of overcoming such drawbacks by using nanostructured lead as a negative electrode. Lead nanowires (NWs) were fabricated by electrochemical deposition in template, which is an easy, cheap, and easily scalable process. Their morphology and crystal structure have been characterized by electron microscopy and X-ray diffraction, respectively. An electrochemical cell simulating…

Performance of Lead-Acid Batteries with Nanostructured Electrodes at Different Temperature

In this work we present innovative lead-acid batteries with nanostructured electrodes, which are cycled in a wide range of temperatures typically of lead-acid commercial batteries (EN 61427-1: 2013). In comparison to parameters usually used to commercial batteries, much more stressful conditions in terms of cut-off, charge/discharge rate and discharge were imposed.

Generazione di luce UV per interazione QPM/SHG in guida ottica di niobato di litio congruente

Surface periodic poling in congruent lithium tantalate

The first demonstration of surface periodic poling of lithium tantalate at high voltages is reported. Periodic domain inversion with mark-to-space ratios close to the optimum 50:50 was successfully achieved down to micrometre periods with good uniformity and repeatability.

CIGS THIN FILM BY ONE-STEP ELECTRODEPOSITION FOR SOLAR CELLS

In this work, we present a cost-effective technique to produce CIGS thin films for solar cells by means of a single-step electrodeposition. In fact, electrodeposition is known as an easy technique for building low cost materials for photovoltaic device processing. Morphological, structural and optical characterization of these films has been performed.

Fabrication of CZTSe/CIGS Nanowire Arrays by One-Step Electrodeposition for Solar-Cell Application

The paper reports some preliminary results concerning the manufacturing process of CuZnSnSe (CZTSe) and CuInGaSe (CIGS) nanowire arrays obtained by one-step electrodeposition for p-n junction fabrication. CZTSe nanowires were obtained through electrodeposition in a polycarbonate membrane by applying a rectangular pulsed current, while their morphology was optimized by appropriately setting the potential and the electrolyte composition. The electrochemical parameters, including pH and composition of the solution, were optimized to obtain a mechanically stable array of nanowires. The samples were characterized by scanning electron microscopy, Raman spectroscopy, and energy-dispersion spectros…

Exploiting the optical quadratic nonlinearity of zinc-blende semiconductors for guided-wave terahertz generation: A material comparison

We present a detailed analysis and comparison of dielectric waveguides made of CdTe, GaP, GaAs and InP for modal phase matched optical difference frequency generation (DFG) in the terahertz domain. From the form of the DFG equations, we derived the definition of a very general figure of merit (FOM). In turn, this FOM enabled us to compare different configurations, by taking into account linear and nonlinear susceptibility dispersion, terahertz absorption, and a rigorous evaluation of the waveguide modes properties. The most efficient waveguides found with this procedure are predicted to approach the quantum efficiency limit with input optical power in the order of kWs.

Dispositivo elettrolizzatore migliorato

Un dispositivo di elettrolizzatore migliorato per la produzione elettrolitica di idrogeno allo stato gassoso

Electrodeposition from molybdate aqueous solutions: a preliminary study

The electrochemistry of molybdenum (Mo) and its oxides is very important for several applications in electrocatalysis,batteries,sensors and in particular for CIGS-based solar cells,where metal Mo is used as back contact.Properties and the fabrication method of Mo films are of fundamental importance,because they could induce significant changes in solar cell performances.The most important issues in the electrochemical behaviour of Mo are the nature and stability of its surface oxides,which are strongly dependent on deposition bath pH.Ivanova et al. (2006) reported that it is possible to accomplish the cathodic reduction of molybdate ions to metallic Mo from electrolytes containing HF.The ad…

CIGS Thin Film by One-Step Electrodeposition Deposition for Solar Cells

Investigation of Annealing Conditions on Electrochemically Deposited CZTS Film on Flexible Molybdenum Foil

In thiswork, the electrodeposition of Cu2ZnSnS4 thin films on molybdenum thin foilwas reported. In order to guarantee co-deposition of elements with different standard electrochemical potential, an aqueous electrolyte added with ligand agents was used. I addition, deposition parameters were carefully chosen, in order to ensure good quality and suitable composition of the films. The deposited films were sulfurized in controlled atmosphere at 580?C, scrutinizing the influence of the annealing conditions on the features of the films. Structure, morphology and composition were investigated by XRD SEM, EDS and Raman spectroscopy. Results reveal the growth of good quality films, with a uniform mo…

Features of randomized electric-field assisted domain inversion in lithium tantalate

We report on bulk and guided-wave second-harmonic generation via random Quasi-Phase-Matching in Lithium Tantalate. By acquiring the far-field profiles at several wavelengths, we extract statistical information on the distribution of the quadratic nonlinearity as well as its average period, both at the surface and in the bulk of the sample. By investigating the distribution in the two regions we demonstrate a non-invasive approach to the study of poling dynamics.

CuInSe2/Zn(S,O,OH) junction by electrochemical and chemical route for photovoltaic applications (GE 2014)

Electrodeposition is a convenient technique for the development of low cost materials for photovoltaic (PV) device processing. Using a single step electrodeposition route, several groups have fabricated CIS (CuInSe) and CIGS (CuInGaSe) films. One of the most important requirements for successful application of one-step electrodeposition film formation is the ability to control composition of the deposited films and to develop polycrystalline microstructures with a low surface roughness and high sintered density.

Guide d’onda a scambio protonico in cristalli ferroelettrici con domini ingegnerizzati superficialmente

Fabrication and Characterization of Polymeric Waveguide using Standard Processing Technology

Nanostructured Electrochemical Devices for Sensing, Energy Conversion and Storage

Nanostructured materials are attracting growing interest for improving performance of devices and systems of large technological interest. In this work, the principal results about the use of nanostructured materials in the field of electrochemical energy storage, electrochemical water splitting, and electrochemical sensing are presented. Nanostructures were fabricated with two different techniques. One of these was the electrodeposition of the desired material inside the channels of a porous support acting as template. The other one was based on displacement reaction induced by galvanic contact between metals with different electrochemical nobility. In the present work, a commercial polyca…