Photoelectrochemical Analysis of Thin Semiconductor Films

Photoelectrochemical Analysis of Thin Semiconductor Films PDF Author: Johanes Handoko Sukamto
Publisher:
ISBN:
Category :
Languages : en
Pages : 424

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Photoelectrochemical Analysis of Thin Semiconductor Films

Photoelectrochemical Analysis of Thin Semiconductor Films PDF Author: Johanes Handoko Sukamto
Publisher:
ISBN:
Category :
Languages : en
Pages : 424

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Photoelectrochemistry and Photovoltaics of Layered Semiconductors

Photoelectrochemistry and Photovoltaics of Layered Semiconductors PDF Author: A. Aruchamy
Publisher: Springer Science & Business Media
ISBN: 9401513015
Category : Science
Languages : en
Pages : 367

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This volume aims at bringing together the results of extensive research done during the last fifteen years on the interfacial photoelectronic properties of the inorganic layered semiconducting materials, mainly in relation to solar energy conversion. Significant contributions have been made both on the fundamental aspects of interface characteristics and on the suitability of the layered materials in photoelectrochemical (semiconductor/electrolyte junctions) and in solid state photovoltaic(Schottky and p-n junctions) cells. New insights into the physical and chemical characteristics of the contact surfaces have been gained and many new applications of these materials have been revealed. In particular, the basal plane surface of the layered materials shows low chemical reactivity and specific electronic behaviour with respect to isotropic solids. In electrochemical systems, the inert nature of these surfaces characterized by saturated chemical bonds has been recognized from studies on charge transfer reactions and catalysis. In addition, studies on the role of the d-band electronic transitions and the dynamics of the photogene rated charge carriers in the relative stability of the photoelectrodes of the transition metal dichalcogenides have deepened the understanding of the interfacial photoreactions. Transition metal layered compounds are also recognized as ideal model compounds for the studies Involving surfaces: photoreactions, adsorption phenomena and catalysis, scanning tunneling microscopy and spectroscopy and epitaxial growth of thin films. Recently, quantum size effects have been investigated in layered semiconductor colloids.

Synthesis and Characterization of Semiconductor Thin Films for Photoelectrochemical Energy Conversion

Synthesis and Characterization of Semiconductor Thin Films for Photoelectrochemical Energy Conversion PDF Author: Nathan Taylor Hahn
Publisher:
ISBN:
Category :
Languages : en
Pages : 366

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The field of solar energy conversion has experienced resurgence in recent years due to mounting concerns related to fossil fuel consumption. The sheer quantity of available solar energy and corresponding opportunity for technological improvement has motivated extensive study of novel light-absorbing semiconductors for solar energy conversion. Often, these studies have focused on new ways of synthesizing and altering thin film semiconductor materials with unique compositions and morphologies in order to optimize them for higher conversion efficiencies. In this dissertation, we discuss the synthesis and electrochemical characterization of a variety of candidate semiconductor materials exhibiting promising characteristics for photoelectrochemical solar energy conversion. Three specific methods of thin film deposition are detailed. The first is a physical vapor deposition technique used to independently tune the morphology and composition of hematite ([alpha]-Fe2O3) based materials. Because of hematite's poor electronic properties, these modifications were able to significantly improve its performance as a photoanode for water oxidation. The second technique is electrodeposition, which was employed to deposit the novel ternary metal oxide, CuBi2O4. The study of these films, along with those prepared by physical vapor deposition, provided insight into the factors limiting the ability of this photo-active material to function as a photocathode for hydrogen evolution from water. The third technique is chemical spray pyrolysis, which was employed to deposit and optimize films of the bismuth chalco-halides BiOI and BiSI. These studies were used to obtain previously unknown properties of these materials relevant to their utilization in photoelectrochemical cells. The manipulation of deposition temperature had significant effects on these properties and dictated the films' overall photoconversion performance.

Photoelectrochemical Hydrogen Production

Photoelectrochemical Hydrogen Production PDF Author: Roel van de Krol
Publisher: Springer Science & Business Media
ISBN: 146141380X
Category : Technology & Engineering
Languages : en
Pages : 322

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Photoelectrochemical Hydrogen Production describes the principles and materials challenges for the conversion of sunlight into hydrogen through water splitting at a semiconducting electrode. Readers will find an analysis of the solid state properties and materials requirements for semiconducting photo-electrodes, a detailed description of the semiconductor/electrolyte interface, in addition to the photo-electrochemical (PEC) cell. Experimental techniques to investigate both materials and PEC device performance are outlined, followed by an overview of the current state-of-the-art in PEC materials and devices, and combinatorial approaches towards the development of new materials. Finally, the economic and business perspectives of PEC devices are discussed, and promising future directions indicated. Photoelectrochemical Hydrogen Production is a one-stop resource for scientists, students and R&D practitioners starting in this field, providing both the theoretical background as well as useful practical information on photoelectrochemical measurement techniques. Experts in the field benefit from the chapters on current state-of-the-art materials/devices and future directions.

Semiconductor Thin Films with Tunable Electronic Structures for Photoelectrochemical Applications

Semiconductor Thin Films with Tunable Electronic Structures for Photoelectrochemical Applications PDF Author: 黃妙言
Publisher:
ISBN:
Category : Physics
Languages : en
Pages : 132

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Proceedings of the Symposium on Photoelectrochemistry

Proceedings of the Symposium on Photoelectrochemistry PDF Author: Krishnan Rajeshwar
Publisher: The Electrochemical Society
ISBN: 9781566771481
Category : Science
Languages : en
Pages : 440

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Study of Novel Metal Oxide Semiconductor Photoanodes for Photoelectrochemical Water Splitting Applications

Study of Novel Metal Oxide Semiconductor Photoanodes for Photoelectrochemical Water Splitting Applications PDF Author: Tilak Poudel
Publisher:
ISBN:
Category : Hydrogen
Languages : en
Pages : 117

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Solar hydrogen is one ideal and sustainable energy source to replace fossil fuel. Solar Photovoltaic (PV) cells normally generate electricity using sunlight, but it is renewable only as long as our sun shines. Converting sunlight into electricity is an efficient way to address energy crisis but harvesting solar energy in the form of chemical energy is a sustainable solution for fueling tomorrows. Storing energy in the form of hydrogen bond is more efficient not only because of its high energy density and but also it is a clean energy source. Hydrogen can be generated in a number of ways, including but not limited to steam reforming, thermolysis, and electrolysis. Photoelectrochemical (PEC) water splitting is one of the most promising methods for solar-to-chemical energy conversion. In order to address the need for clean and renewable energy, recent trends in global CO2 emissions and energy production are analyzed, and the photoelectrochemical properties of multi-metal oxide based thin films are presented. Bismuth vanadate (BiVO4), barium bismuth niobate (Ba2BiNbO6), and antimony vanadate (SbVO4) were investigated for use as photoelectrodes in PEC water splitting for solar hydrogen production. This dissertation starts with synthesis, deposition, and characterization of antimony vanadate and Sb alloyed bismuth vanadate thin films to observe their photoelectrochemical ability to split water. Antimony doping in bismuth vanadate thin films prompts to modify valence and conduction band edges of bismuth vanadate. It has been found that Sb alloying with less than 20% wt. improves the electron conductivity and consequently leads to significant enhancement of photocurrents without creating secondary phases. The hole mobility is further improved by incorporating NaF and metallic Ni on the surface of the electrode. The NaF incorporation is believed to reduce electron effective mass and therefore increased electron mobility by suppressing scattering centers. As a result, antimony doped thin films exhibited much improved performance in PEC water splitting as compared to pure sputtered BiVO4. The metallic Ni deposition on the surface of Sb-doped BiVO4 acted as electrode corrosion inhibitor. But we found that Ni topping can enhance the stability of electrode in strong acidic solutions at the cost of reducing its optical absorption and hence lowering its photon-to-electron conversion efficiency. However, surface modification of thin films using various stack structure and oxides coatings helped to enhance their stability along with the oxygen evolution catalysis. Large area Bi-based quaternary oxides (Ba2Bi1.4Nb0.6O6 and Ba2BiNbO6) were deposited using RF sputtering deposition and the effects of surface-modification was also investigated using various electrochemical methods. Thin film uniformity was obtained by incorporating oxygen gas in the sputtering plasma. Photoelectrochemical thin films with higher stability in aqueous solution and better corrosion resistant were fabricated, analyzed, and tested. Capacitance-voltage measurement was used to measure the chemical kinetics of interfacial electron transfer of the system. Charge-carrier mobility was extremely limited by the rate of recombination, while the surface chemistry was altered by using Oxygen Evolution Reaction (OER) catalysts. Using the OER catalysts significantly reduced the surface recombination losses thereby extending hole carrier lifetime. Finally, a novel, high-throughput, combinatorial approach for the material synthesis and screening of mixed-metal oxides for photoanode design was developed. This methodology relies on controlling stoichiometric ratio of different sputtering yield metal oxides. After fabrication, the photoelectrochemical properties of oxide electrodes can be fully characterized by using various optical and electrochemical technique.

Photoelectrolysis of Water at Semiconductor Electrodes

Photoelectrolysis of Water at Semiconductor Electrodes PDF Author: Jean Pierre Hirtz
Publisher:
ISBN:
Category : Metal oxide semiconductors
Languages : en
Pages : 184

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Photoelectrochemical Water Splitting

Photoelectrochemical Water Splitting PDF Author: Zhebo Chen
Publisher: Springer Science & Business Media
ISBN: 1461482984
Category : Science
Languages : en
Pages : 130

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Book Description
This book outlines many of the techniques involved in materials development and characterization for photoelectrochemical (PEC) – for example, proper metrics for describing material performance, how to assemble testing cells and prepare materials for assessment of their properties, and how to perform the experimental measurements needed to achieve reliable results towards better scientific understanding. For each technique, proper procedure, benefits, limitations, and data interpretation are discussed. Consolidating this information in a short, accessible, and easy to read reference guide will allow researchers to more rapidly immerse themselves into PEC research and also better compare their results against those of other researchers to better advance materials development. This book serves as a “how-to” guide for researchers engaged in or interested in engaging in the field of photoelectrochemical (PEC) water splitting. PEC water splitting is a rapidly growing field of research in which the goal is to develop materials which can absorb the energy from sunlight to drive electrochemical hydrogen production from the splitting of water. The substantial complexity in the scientific understanding and experimental protocols needed to sufficiently pursue accurate and reliable materials development means that a large need exists to consolidate and standardize the most common methods utilized by researchers in this field.

Photoelectrochemical Activity of Titanium Dioxide Thin Films

Photoelectrochemical Activity of Titanium Dioxide Thin Films PDF Author: Aida Mehdinezhad Roshan
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Titanium dioxide (TiO2) is considered as an oxide semiconductor with several unique properties, including environmental sensing capabilities, biocompatibility and photocurrent generation, long-term stability, cost efficiency, and chemical inertness. TiO2 thin films have a wide range of applications in dye-sensitized solar cells. TiO2 films have been deposited on two different substrates, aluminum and titanium. Two different methods used for deposition of the thin films namely: Plasma Electrolytic Oxidation (PEO) and Physical Vapor Deposition (PVD). In order to study the effect of roughness of the substrate on photocurrent generation of the deposited films, one group of substrates were "patterned" by Electrolytic Plasma Processing (EPP) prior to deposition. A "hill and valley" morphology was observed on the uppermost layer of the EPP-treated substrates. The microstructure and also roughness of the EPP-treated substrates were characterized by Scanning Electron Microscopy (SEM) and Profilometry. Similarly, the deposited TiO2 thin films were also characterized by SEM, Energy Dispersive Spectroscopy (EDS), Raman, Transmission Electron Microscopy (TEM), X-ray Diffractometry (XRD), and Profilometry. It was found that the PEO deposited film on titanium substrate was composed of anatase and the film on the aluminum substrate was amorphous. The average thickness of the PEO deposited films was about 6-10 microns. TiO2 thin films deposited by DC magnetron sputtering were found to be almost amorphous with an average thickness of 650 nm. High resolution TEM analysis showed some areas of crystallinity with a grain size of ~5 nm. Photoelectrocurrent measurements were then performed on all deposited films by a standard single-compartment, three-electrode electrochemical cell. It has been observed that the films deposited by PVD technique have a much higher quality and produce much higher photocurrent comparing to ones of PEO method.