Download or read book Controlled Synthesis of ZnO Nanowires Towards the Fabrication of Solar Cells written by Dongshan Yu and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In recent years, quasi-one-dimensional materials have attracted a lot of research attention due to their remarkable properties, and their potential as building blocks for nanoscale electronic and optoelectronic devices. A modified chemical vapor deposition (CVD) method has been used to synthesize ZnO nanowires. Electron microscopy and other characterization techniques show that nanowires having distinct morphologies when grown under different conditions. The effects of reaction parameters including reaction time, temperature, carrier gas flow rate, substrates and catalyst material upon the size, shape, and density of ZnO nanowire arrays have been investigated. Excitonic solar cells -including Gratzel-type cells, organic and hybrid organic/inorganic solar cells- are promising devices for inexpensive, large-scale solar energy conversion. Hybrid organic/inorganic solar cells are made from composites of conjugated polymers with nanostructure metal oxides, in which the polymer component serves the function of both light absorber and hole conductor, and the ZnO nanowire arrays act as the electron conductors. Organic solar cells have been fabricated from environmentally friendly water-soluble polymers and ZnO nanowire arrays.
Download or read book Large scale Patterned Oxide Nanostructures written by Xudong Wang and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanotechnology is experiencing a flourishing development in a variety of fields covering all of the areas from science to engineering and to biology. As an active field in nanotechnology, the work presented in this dissertation is mostly focused on the fundamental study about the fabrication and assembly of functional oxide nanostructures. In particular, Zinc Oxide, one of the most important functional semiconducting materials, is the core objective of this research, from the controlled growth of nanoscale building blocks to understanding their properties and to how to organize these building blocks. Thermal evaporation process based on a single-zone tube furnace has been employed for synthesizing a range of 1D nanostructures. By controlling the experimental conditions, different morphologies, such as ultra-small ZnO nanobelts, mesoporous ZnO nanowires and core-shell nanowire were achieved. In order to pattern the nanostructures, a large-scale highly-ordered nanobowl structure based on the self-assembly of submicron spheres was created and utilized as patterning template. The growth and patterning techniques were thereafter integrated for aligning and patterning of ZnO nanowires. The aligning mechanisms and growth conditions were thoroughly studied so as to achieve a systematic control over the morphology, distribution and density. The related electronic and electromechanical properties of the aligned ZnO nanowires were investigated. The feasibility of some potential applications, such as photonic crystals, solar cells and sensor arrays, has also been studied. This research may set a foundation for many industrial applications from controlled synthesis to nanomanufacturing.
Download or read book ZnO Nanowires for Dye Sensitized Solar Cells written by Simas Rackauskas and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This chapter provides a broad review of the latest research activities focused on the synthesis and application of ZnO nanowires (NWs) for dye-sensitized solar cells (DSCs) and composed of three main sections. The first section briefly introduces DSC-working principles and ZnO NW application advantages and stability issues. The next section reviews ZnO NW synthesis methods, demonstrating approaches for controlled synthesis of different ZnO NW morphology and discussing how this effects the overall efficiency of the DSC. In the last section, the methods for ZnO NW interface modification with various materials are discussed, which include ZnO core-shell structures with semiconductive or protective layers, ZnO NW hybrid structures with other materials, such as nanoparticles, quantum dots and carbon nanomaterials and their benefit for charge and light transport in DSCs. The review is concluded with some perspectives and outlook on the future developments in the ZnO nanowire application for DSCs.
Download or read book Fundamental Study of the Fabrication of Zinc Oxide Nanowires and Its Dye sensitized Solar Cell Applications written by Mallarie DeShea McCune and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Because of its excellent and unique physical properties, ZnO nanowires have been widely used in numerous scientific fields such as sensors, solar cells, nanogenerators, etc. Although it is believed that single crystal ZnO has a much higher electron transfer rate than TiO2, it was found that ZnO nanowire-based dye-sensitized solar cells (DSSCs) have lower efficiencies than TiO2 nanoparticle-based DSSCs because the density and surface area of ZnO nanowires are usually lower than that of TiO2 nanoparticles, limiting the cell's light absorption, and because the open-root structure of ZnO nanowires results in electron back transfer that causes charge shortage of the cell. Here, experimental studies were performed that utilize strategic manipulations of the design of the ZnO nanowire based DSSCs in efforts to address and solve its key challenges. It was shown that by incorporating various blocking layers into the design of the cell, the performance of the DSSC can be improved. Specifically, by placing a hybrid blocking layer of TiO2-P4VP polymer between the substrate and the ZnO nanowires, the conversion efficiency of the cell was 43 times higher than that of a cell without this blocking layer due to the reduction of electron back transfer. Furthermore, in efforts to improve the surface area of the ZnO nanowire array, unique three dimensional structures of ZnO nanowires were fabricated. It was found that by significantly improving the overall density and surface area of the ZnO nanowire array through distinctive hierarchal nanowire structures, the light harvesting efficiency and electron transport were enhanced allowing the DSSC to reach 5.20%, the highest reported value for 3D ZnO NW based DSSCs. Additionally, the development of a theoretical model was explored in efforts to investigate how the geometry of ZnO nanowires affects the incident photon-to-current conversion efficiency of 1D ZnO nanowire-based N719-sensitized solar cells at the maximum absorption wavelength of 543 nm.
Download or read book One dimensional Zinc Oxide Nanomaterials written by Benjamin A. Weintraub and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: As humanly engineered materials systems approach the atomic scale, top-down manufacturing approaches breakdown and following nature's example, bottom-up or self-assembly methods have the potential to emerge as the dominant paradigm. Synthesis of one-dimensional nanomaterials takes advantage of such self-assembly manufacturing techniques, but until now most efforts have relied on high temperature vapor phase schemes which are limited in scalability and compatibility with organic materials. The solution-phase approach is an attractive low temperature alternative to overcome these shortcomings. To this end, this thesis is a study of the rationale solution-phase synthesis of ZnO nanowires and applications in photovoltaics. The following thesis goals have been achieved: rationale synthesis of a single ZnO nanowire on a polymer substrate without seeding, design of a wafer-scale technique to control ZnO nanowire array density using layer-by-layer polymers, determination of optimal nanowire field emitter density to maximize the field enhancement factor, design of bridged nanowires across metal electrodes to order to circumvent post-synthesis manipulation steps, electrical characterization of bridged nanowires, rationale solution-phase synthesis of long ZnO nanowires on optical fibers, fabrication of ZnO nanowire dye-sensitized solar cells on optical fibers, electrical and optical characterization of solar cell devices, comparison studies of 2-D versus 3-D nanowire dye-sensitized solar cell devices, and achievement of 6-fold solar cell power conversion efficiency enhancement using a 3-D approach. The thesis results have implications in nanomanufacturing scale-up and next generation photovoltaics.
Download or read book Controlled Nanofabrication written by Liu Ru-Shi and published by CRC Press. This book was released on 2012-10-17 with total page 770 pages. Available in PDF, EPUB and Kindle. Book excerpt: When the size and the shape of materials are reduced to the nanoscale dimension, their physical and chemical properties can change dramatically. This book demonstrates the controlled size and shape of nanostructured materials and their applications. The applications cover photocatalysts, biomedicals, nanomaterials, fuel cells and supercapacitors, l
Download or read book ZnO Nanostructures written by Yue Zhang and published by Royal Society of Chemistry. This book was released on 2017-06-21 with total page 307 pages. Available in PDF, EPUB and Kindle. Book excerpt: As wide band semiconductors with rich morphologies and interesting electric, optical, mechanical and piezoelectric properties, ZnO nanostructures have great potential in applications, such as strain sensors, UV detectors, blue LED, nano generators, and biosensors. ZnO Nanostructures: Fabrication and Applications covers the controllable synthesis and property optimization of ZnO nanostructures through to the preparation and performance of nanodevices for various applications. The book also includes recent progress in property modulation of ZnO nanomaterials and new types of devices as well as the latest research on self-powered devices and performance modulation of ZnO nanodevices by multi-field coupled effects. Authored by a leading researcher working within the field, this volume is applicable for those working in nanostructure fabrication and device application in industry and academia and is appropriate from advanced undergraduate level upwards.
Download or read book Hydrothermal Synthesis of Zinc Oxide Nanowire Arrays for Photovoltaic Applications written by Jian Wei Jayce Cheng and published by . This book was released on 2016 with total page 171 pages. Available in PDF, EPUB and Kindle. Book excerpt: Zinc oxide (ZnO) nanowires with excellent crystal quality can be grown vertically aligned from a substrate using hydrothermal synthesis, a low-cost, scalable process that is compatible with many semiconductor processing techniques. However, precise control over nanowire array dimensions such as nanowire spacing, diameter, length, and alignment, which is important for optoelectronic device applications, has proven elusive due to lack of understanding regarding fundamental aqueous growth mechanisms at the nanoscale. Here, we utilize electron-beam lithography to template ZnO seed layers, demonstrating that seed layer engineering via judicious choice of seed deposition conditions and annealing can yield well-aligned nanowire arrays with single nanowire spatial precision on a variety of device relevant substrates. Subsequently, we use bottom-up patterning techniques and investigate the competition between diffusive transport and surface reaction in hydrothermal growth to achieve control over nanowire spacing and enhanced nanowire array uniformity over length scales suitable for photovoltaic (PV) device fabrication. By analyzing the role of temperature, concentration, and areal seed density on the balance between diffusion vs. reaction rates at the solution-nanowire interface, we show that the c-facet grows via the direct incorporation mechanism. With this knowledge, we use additives to shift the nanowire growth system into a reaction-limited regime, making nanowire growth rate independent of the patterned template. As a consequence, we achieve ZnO nanowire array uniformity that is critical for device applications.
Download or read book Zinc Oxide Nanostructures Synthesis and Characterization written by Sotirios Baskoutas and published by MDPI. This book was released on 2018-12-04 with total page 303 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a printed edition of the Special Issue "Zinc Oxide Nanostructures: Synthesis and Characterization" that was published in Materials
Download or read book Solar Cells written by Leonid A. Kosyachenko and published by BoD – Books on Demand. This book was released on 2011-11-09 with total page 506 pages. Available in PDF, EPUB and Kindle. Book excerpt: The second book of the four-volume edition of "Solar cells" is devoted to dye-sensitized solar cells (DSSCs), which are considered to be extremely promising because they are made of low-cost materials with simple inexpensive manufacturing procedures and can be engineered into flexible sheets. DSSCs are emerged as a truly new class of energy conversion devices, which are representatives of the third generation solar technology. Mechanism of conversion of solar energy into electricity in these devices is quite peculiar. The achieved energy conversion efficiency in DSSCs is low, however, it has improved quickly in the last years. It is believed that DSSCs are still at the start of their development stage and will take a worthy place in the large-scale production for the future.
Download or read book Nanomaterials for Solar Cell Applications written by Sabu Thomas and published by Elsevier. This book was released on 2019-06-12 with total page 761 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanomaterials for Solar Cell Applications provides a review of recent developments in the field of nanomaterials based solar cells. It begins with a discussion of the fundamentals of nanomaterials for solar calls, including a discussion of lifecycle assessments and characterization techniques. Next, it reviews various types of solar cells, i.e., Thin film, Metal-oxide, Nanowire, Nanorod and Nanoporous materials, and more. Other topics covered include a review of quantum dot sensitized and perovskite and polymer nanocomposites-based solar cells. This book is an ideal resource for those working in this evolving field of nanomaterials and renewable energy. - Provides a well-organized approach to the use of nanomaterials for solar cell applications - Discusses the synthesis, characterization and applications of traditional and new material - Includes coverage of emerging nanomaterials, such as graphene, graphene-derivatives and perovskites
Download or read book Physical Chemistry for Chemists and Chemical Engineers written by Alexander V. Vakhrushev and published by CRC Press. This book was released on 2018-09-03 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume is based on different aspects of chemical technology that are associated with research and the development of theories for chemical engineers, helping to bridge the gap between classical analysis and modern, real-life applications. Taking an interdisciplinary approach, the authors present the current state-of-the-art technology in key materials with an emphasis on the rapidly growing technologies.
Download or read book Multifunctional Oxide Based Materials From Synthesis to Application written by Teofil Jesionowski and published by MDPI. This book was released on 2019-09-03 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book deals with novel aspects and perspectives in metal oxide and hybrid material fabrication. The contributions are mainly focused on the search for a new group of advanced materials with designed physicochemical properties, especially an expanded porous structure and defined surface activity. The proposed technological procedures result in an enhanced activity of the synthesized hybrid materials, which is of great importance when considering their potential fields of application. The use of such materials in different technological disciplines, including aspects associated with environmental protection, allows for the verification of the proposed synthesis method. Thus, it can be stated that those aspects are of interdisciplinary character and may be located at the interface of three scientific disciplines—chemistry, materials science, and engineering—as well as environmental protection. Furthermore, the presented scientific scope is in some way an answer to the continuous demand for such types of materials and opens new perspectives for their practical use
Download or read book ZnO Nanostructure Synthesis Laser Direct Writing Process for Optoelectronic Devices written by DAEHO LEE and published by . This book was released on 2012 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt: Zinc oxide (ZnO) has a long history of usage in electronics. Recently, ZnO has been gathering great interest of researchers in nanoscience due to its diverse and versatile morphologies such as nanoparticles (NP), nanowires (NW), nanorods, nanotubes, nanohelixes, etc. This dissertation deals with studies covering from the synthesis of ZnO nanostructures to deposition & patterning methods and their applications for optoelectronic devices such as transparent electrodes, active layers for thin film transistor and photovoltaics. A very well-dispersed, transparent and concentration-tunable ZnO NP solution was successfully synthesized with a new process. Highly transparent ZnO thin films were fabricated by spin coating and subsequent ultra short-pulsed UV laser annealing was performed to change the film properties. While as-deposited NP thin films were not electrically conductive, laser annealing imparted a substantial conductivity increase. Thus, selective annealing for conductive patterns directly on the NP thin film without a photolithographic process was achieved. The conductivity is by a factor of 105 higher than that of the previously reported furnace-annealed ZnO NP films and even comparable to that of vacuum-deposited, impurity-doped ZnO films within a factor of 10. The ZnO film obtained from the process developed in this work has been applied to the fabrication of a thin film transistor (TFT) showing enhanced performance compared with the TFT fabricated on furnace annealed ZnO film. The ZnO TFT performance test reveals that by just changing the laser annealing parameters the solution-deposited ZnO thin film properties can be tuned suitable for both transparent conductors and semiconductor active layers. Two kinds of nanomaterial patterning methods via direct writing have been demonstrated. First, laser-assisted nanoimprinting of metal and semiconductor nanoparticles has been presented as a large area one step patterning method. With the method, submicron structures including mesh, line, nanopillar and nanowire arrays were fabricated on various kinds of wafer scale substrates. Using the rapid laser-based nanolithography, the prohibitive constraints of e-beam patterning could be overcome. Therefore, this method opens a way to the fabrication of electronic and energy devices with high throughput and ultra low-cost. Second, a drop on demand (DOD) inkjet printing of ZnO seed layers integrated with a CAD (computer aided design) system for a fully digital selective ZnO NW array growth has been discussed. Through proper natural convection suppression during the hydrothermal growth, successful ZnO nanowire local growth could be achieved. Without any need for the photolithographic process or stamp preparation, the NW growth location can be easily modified with high degree of freedom. These two methods are compatible with flexible plastic substrates. As an application of ZnO nanostructures for high efficiency solar cells, ZnO dye-sensitized solar cells (DSSCs) with greatly enhanced surface area for higher dye loading and light harvesting were demonstrated. The selective growth of "nanoforests" composed of high density, long branched tree-like multi generation hierarchical ZnO nanowire photoanodes by utilizing seed particles and a capping polymer increased the energy conversion efficiency significantly. The overall light-conversion efficiency of the branched ZnO nanowire DSSCs was almost 5 times higher than the efficiency of DSSCs constructed by upstanding ZnO nanowires. A parametric study to determine the optimum hierarchical ZnO nanowire photoanode was performed through the combination of both length-wise and branched growth processes.
Download or read book Toward the Optimization of Low temperature Solution based Synthesis of ZnO Nanostructures for Device Applications written by Hatim Alnoor and published by Linköping University Electronic Press. This book was released on 2017-10-06 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt: One-dimensional (1D) nanostructures (NSs) of Zinc Oxide (ZnO) such as nanorods (NRs) have recently attracted considerable research attention due to their potential for the development of optoelectronic devices such as ultraviolet (UV) photodetectors and light-emitting diodes (LEDs). The potential of ZnO NRs in all these applications, however, would require synthesis of high crystal quality ZnO NRs with precise control over the optical and electronic properties. It is known that the optical and electronic properties of ZnO NRs are mostly influenced by the presence of native (intrinsic) and impurities (extrinsic) defects. Therefore, understanding the nature of these intrinsic and extrinsic defects and their spatial distribution is critical for optimizing the optical and electronic properties of ZnO NRs. However, identifying the origin of such defects is a complicated matter, especially for NSs, where the information on anisotropy is usually lost due to the lack of coherent orientation. Thus, the aim of this thesis is towards the optimization of the lowtemperature solution-based synthesis of ZnO NRs for device applications. In this connection, we first started with investigating the effect of the precursor solution stirring durations on the deep level defects concentration and their spatial distribution along the ZnO NRs. Then, by choosing the optimal stirring time, we studied the influence of ZnO seeding layer precursor’s types, and its molar ratios on the density of interface defects. The findings of these investigations were used to demonstrate ZnO NRs-based heterojunction LEDs. The ability to tune the point defects along the NRs enabled us further to incorporate cobalt (Co) ions into the ZnO NRs crystal lattice, where these ions could occupy the vacancies or interstitial defects through substitutional or interstitial doping. Following this, high crystal quality vertically welloriented ZnO NRs have been demonstrated by incorporating a small amount of Co into the ZnO crystal lattice. Finally, the influence of Co ions incorporation on the reduction of core-defects (CDs) in ZnO NRs was systematically examined using electron paramagnetic resonance (EPR).
Download or read book Growth Doping and Characterization of ZnO Nanowires written by Svetlana Spitsina and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Springer Handbook of Inorganic Photochemistry written by Detlef Bahnemann and published by Springer Nature. This book was released on 2022-06-25 with total page 1914 pages. Available in PDF, EPUB and Kindle. Book excerpt: The handbook comprehensively covers the field of inorganic photochemistry from the fundamentals to the main applications. The first section of the book describes the historical development of inorganic photochemistry, along with the fundamentals related to this multidisciplinary scientific field. The main experimental techniques employed in state-of-art studies are described in detail in the second section followed by a third section including theoretical investigations in the field. In the next three sections, the photophysical and photochemical properties of coordination compounds, supramolecular systems and inorganic semiconductors are summarized by experts on these materials. Finally, the application of photoactive inorganic compounds in key sectors of our society is highlighted. The sections cover applications in bioimaging and sensing, drug delivery and cancer therapy, solar energy conversion to electricity and fuels, organic synthesis, environmental remediation and optoelectronics among others. The chapters provide a concise overview of the main achievements in the recent years and highlight the challenges for future research. This handbook offers a unique compilation for practitioners of inorganic photochemistry in both industry and academia.
