Showing papers on "Thin film published in 2006"
TL;DR: In this paper, the authors describe the synthesis of bilayer graphene thin films deposited on insulating silicon carbide and report the characterization of their electronic band structure using angle-resolved photoemission.
Abstract: We describe the synthesis of bilayer graphene thin films deposited on insulating silicon carbide and report the characterization of their electronic band structure using angle-resolved photoemission. By selectively adjusting the carrier concentration in each layer, changes in the Coulomb potential led to control of the gap between valence and conduction bands. This control over the band structure suggests the potential application of bilayer graphene to switching functions in atomic-scale electronic devices.
2,988 citations
TL;DR: In this paper, the effect of the zinc precursor type, the aging of the starting solution, the substrate temperature and a vacuum-annealing treatment on the electrical, morphological, structural and optical properties was studied, in order to obtain conductive and transparent zinc oxide thin films.
2,780 citations
TL;DR: New semiconducting liquid-crystalline thieno[3,2-b ]thiophene polymers are reported on, the enhancement in charge-carrier mobility achieved through highly organized morphology from processing in the mesophase, and the effects of exposure to both ambient and low-humidity air on the performance of transistor devices.
Abstract: Organic semiconductors that can be fabricated by simple processing techniques and possess excellent electrical performance, are key requirements in the progress of organic electronics. Both high semiconductor charge-carrier mobility, optimized through understanding and control of the semiconductor microstructure, and stability of the semiconductor to ambient electrochemical oxidative processes are required. We report on new semiconducting liquid-crystalline thieno[3,2-b ]thiophene polymers, the enhancement in charge-carrier mobility achieved through highly organized morphology from processing in the mesophase, and the effects of exposure to both ambient and low-humidity air on the performance of transistor devices. Relatively large crystalline domain sizes on the length scale of lithographically accessible channel lengths (∼200 nm) were exhibited in thin films, thus offering the potential for fabrication of single-crystal polymer transistors. Good transistor stability under static storage and operation in a low-humidity air environment was demonstrated, with charge-carrier field-effect mobilities of 0.2–0.6 cm2 V−1 s−1 achieved under nitrogen.
2,011 citations
TL;DR: An overview of the state of the art in ferroelectric thin films is presented in this paper, where the authors review applications: micro-systems' applications, applications in high frequency electronics, and memories based on Ferroelectric materials.
Abstract: An overview of the state of art in ferroelectric thin films is presented. First, we review applications: microsystems' applications, applications in high frequency electronics, and memories based on ferroelectric materials. The second section deals with materials, structure (domains, in particular), and size effects. Properties of thin films that are important for applications are then addressed: polarization reversal and properties related to the reliability of ferroelectric memories, piezoelectric nonlinearity of ferroelectric films which is relevant to microsystems' applications, and permittivity and loss in ferroelectric films-important in all applications and essential in high frequency devices. In the context of properties we also discuss nanoscale probing of ferroelectrics. Finally, we comment on two important emerging topics: multiferroic materials and ferroelectric one-dimensional nanostructures. (c) 2006 American Institute of Physics.
1,632 citations
TL;DR: In this article, thin films of silicon-doped Fe2O3 were deposited by APCVD (atmospheric pressure chemical vapor deposition) from Fe(CO)5 and TEOS (tetraethoxysilane) on SnO2-coated glass at 415 °C.
Abstract: Thin films of silicon-doped Fe2O3 were deposited by APCVD (atmospheric pressure chemical vapor deposition) from Fe(CO)5 and TEOS (tetraethoxysilane) on SnO2-coated glass at 415 °C. HRSEM reveals a highly developed dendritic nanostructure of 500 nm thickness having a feature size of only 10−20 nm at the surface. Real surface area determination by dye adsorption yields a roughness factor of 21. XRD shows the films to be pure hematite with strong preferential orientation of the [110] axis vertical to the substrate, induced by silicon doping. Under illumination in 1 M NaOH, water is oxidized at the Fe2O3 electrode with higher efficiency (IPCE = 42% at 370 nm and 2.2 mA/cm2 in AM 1.5 G sunlight of 1000 W/m2 at 1.23 VRHE) than at the best reported single crystalline Fe2O3 electrodes. This unprecedented efficiency is in part attributed to the dendritic nanostructure which minimizes the distance photogenerated holes have to diffuse to reach the Fe2O3/electrolyte interface while still allowing efficient light abso...
1,442 citations
TL;DR: It is shown how the morphology of drop-deposited nanoparticle films is controlled by evaporation kinetics and particle interactions with the liquid–air interface, and this self-assembly mechanism produces monolayers with exceptional long-range ordering that are compact over macroscopic areas, despite the far-from-equilibriumevaporation process.
Abstract: When a drop of a colloidal solution of nanoparticles dries on a surface, it leaves behind coffee-stain-like rings of material with lace-like patterns or clumps of particles in the interior. These non-uniform mass distributions are manifestations of far-from-equilibrium effects, such as fluid flows and solvent fluctuations during late-stage drying. However, recently a strikingly different drying regime promising highly uniform, long-range-ordered nanocrystal monolayers has been found. Here we make direct, real-time and real-space observations of nanocrystal self-assembly to reveal the mechanism. We show how the morphology of drop-deposited nanoparticle films is controlled by evaporation kinetics and particle interactions with the liquid-air interface. In the presence of an attractive particle-interface interaction, rapid early-stage evaporation dynamically produces a two-dimensional solution of nanoparticles at the liquid-air interface, from which nanoparticle islands nucleate and grow. This self-assembly mechanism produces monolayers with exceptional long-range ordering that are compact over macroscopic areas, despite the far-from-equilibrium evaporation process. This new drop-drying regime is simple, robust and scalable, is insensitive to the substrate material and topography, and has a strong preference for forming monolayer films. As such, it stands out as an excellent candidate for the fabrication of technologically important ultra thin film materials for sensors, optical devices and magnetic storage media.
1,039 citations
Patent•
10 Oct 2006TL;DR: In this paper, a thin-film semiconductor and a method of its fabrication use induced crystallization and aggregation of a nanocrystal seed layer to form a merged-domain layer.
Abstract: A thin film semiconductor and a method of its fabrication use induced crystallization and aggregation of a nanocrystal seed layer to form a merged-domain layer. The nanocrystal seed layer is deposited onto a substrate surface within a defined boundary. A reaction temperature below a boiling point of a reaction solution is employed. A thin film metal-oxide transistor and a method of its production employ the thin film semiconductor as a channel of the transistor. The merged-domain layer exhibits high carrier mobility.
1,026 citations
Patent•
22 Nov 2006TL;DR: In this article, a transparent conductive film is produced by growing ZnO doped with a group III element oxide on a substrate and has a region with a crystal structure in which a c-axis grows along a plurality of different directions.
Abstract: A ZnO-based transparent conductive film is produced by growing ZnO doped with a group III element oxide on a substrate and has a region with a crystal structure in which a c-axis grows along a plurality of different directions. The transparent conductive film produced by growing ZnO doped with a group III element oxide on a substrate has a ZnO (002) rocking curve full width at half maximum of about 13.5° or more. ZnO is doped with a group III element oxide so that the ratio of the group III element oxide in the transparent conductive film is about 7% to about 40% by weight. The transparent conductive film is formed on the substrate with a SiNx thin film provided therebetween. The transparent conductive film is formed on the substrate by a thin film formation method with a bias voltage applied to the substrate.
1,021 citations
Patent•
27 Jul 2006TL;DR: In this article, an organic light-emitting display (OLED) and a method of fabricating the OLED includes: a substrate including a pixel region and a non-pixel region, a gate electrode arranged in the nonpixel region of the substrate, a first insulating layer arranged on the substrate having the gate electrode formed thereon, and having an open groove on an upper surface of a region opposite to the gate electrodes, a semiconductor layer buried in the groove and including a source region, channel region, and a drain region; and an organic thin film layer arranged
Abstract: An Organic Light Emitting Display (OLED) and a method of fabricating the OLED includes: a substrate including a pixel region and a non-pixel region; a gate electrode arranged in the non-pixel region of the substrate; a first insulating layer arranged on the substrate having the gate electrode formed thereon, and having an open groove on an upper surface of a region opposite to the gate electrode; a semiconductor layer buried in the groove and including a source region, a channel region and a drain region; and an organic thin film layer arranged in the pixel region of the substrate. A common electrode is arranged between the drain region of the semiconductor layer and the organic thin film layer to electrically couple the drain region to the organic thin film layer.
1,006 citations
Patent•
07 Jun 2006TL;DR: In this article, a thin-film transistor has a semiconductor thin film including zinc oxide, a protection film formed on entirely the upper surface of the semiconductor, a gate insulating film forming on the protection film, and a gate electrode formed on the gate-insulating film above the semiconducting layer.
Abstract: A thin film transistor has a semiconductor thin film including zinc oxide, a protection film formed on entirely the upper surface of the semiconductor thin film, a gate insulating film formed on the protection film, a gate electrode formed on the gate insulating film above the semiconductor thin film, and a source electrode and drain electrode formed under the semiconductor thin film so as to be electrically connected to the semiconductor thin film.
989 citations
TL;DR: In this paper, a comparative study on transparent conductive thin films made with two kinds of commercial carbon nanotubes: HiPCO and arc-discharge nanotube was carried out.
Abstract: We have carried out comparative studies on transparent conductive thin films made with two kinds of commercial carbon nanotubes: HiPCO and arc-discharge nanotubes. These films have been further exploited as hole-injection electrodes for organic light-emitting diodes (OLEDs) on both rigid glass and flexible substrates. Our experiments reveal that films based on arc-discharge nanotubes are overwhelmingly better than HiPCO-nanotube-based films in all of the critical aspects, including surface roughness, sheet resistance, and transparency. Further improvement in arc-discharge nanotube films has been achieved by using PEDOT passivation for better surface smoothness and using SOCl2 doping for lower sheet resistance. The optimized films show a typical sheet resistance of ∼160 Ω/□ at 87% transparency and have been used successfully to make OLEDs with high stabilities and long lifetimes.
TL;DR: In this article, the development and application of magnetron sputtering systems for ionized physical vapor deposition (IPVD) is reviewed, and the application of a secondary discharge, inductively coupled plasma magnetron (ICP-MS), microwave amplified magnetron, and self-sustained sputtering (SSS) is discussed as well as the hollow cathode magnetron discharges.
TL;DR: In this article, the authors demonstrate the correlation between microstructure and mechanical as well as tribological properties of hard ceramic coatings and demonstrate that nanostructure dependent hardness increase (compared to hardness of the bulk counterparts) sustains higher annealing temperatures than hardness increase due to an increased density of point-and/or line-defects.
TL;DR: In this article, the magnetic moment was observed in undoped semiconducting or insulating oxides to become ferromagnetic at room temperature on MgO substrates, where the magnetic field was applied parallel to the film plane.
Abstract: Remarkable room-temperature ferromagnetism was observed in undoped $\mathrm{Ti}{\mathrm{O}}_{2}$, $\mathrm{Hf}{\mathrm{O}}_{2}$, and ${\mathrm{In}}_{2}{\mathrm{O}}_{3}$ thin films. The magnetic moment is rather modest in the case of ${\mathrm{In}}_{2}{\mathrm{O}}_{3}$ films on MgO substrates (while on ${\mathrm{Al}}_{2}{\mathrm{O}}_{3}$ substrates, it is negative showing diamagnetism) when the magnetic field was applied parallel to the film plane. In contrast, it is very large in the other two cases (about 20 and $30\phantom{\rule{0.3em}{0ex}}\mathrm{emu}∕{\mathrm{cm}}^{3}$ for $200\text{\ensuremath{-}}\mathrm{nm}$-thick $\mathrm{Ti}{\mathrm{O}}_{2}$ and $\mathrm{Hf}{\mathrm{O}}_{2}$ films, respectively). Since bulk $\mathrm{Ti}{\mathrm{O}}_{2}$, $\mathrm{Hf}{\mathrm{O}}_{2}$, and ${\mathrm{In}}_{2}{\mathrm{O}}_{3}$ are clearly diamagnetic, and moreover, there are no contaminations in any substrate, we must assume that the thin film form, which might create necessary defects or oxygen vacancies, would be the reason for undoped semiconducting or insulating oxides to become ferromagnetic at room temperature.
17 Nov 2006
TL;DR: In this paper, the authors discuss the use of pulsed laser deformation for the removal of complex materials and their application in biomedical applications. But they do not discuss the application of such deformation in drug delivery systems.
Abstract: SECTION I. 1. Pulsed Laser Deposition of Complex Materials: Progress Towards Applications (D. Norton). SECTION II. 2. Resonant Infrared Pulsed Laser Ablation and Deposition of Thin Polymer Films (D. Bubb & R. Haglund). 3. Deposition of Polymers and Biomaterials Using the Matrix Assisted Pulsed Laser Eveporation (MAPLE) Process (A. Pique). 4. In situ Diagnostics by High Pressure RHEED during PLD (G. Rijnders & D. Blank). 5. Ultra-fast laser Ablation and Film Deposition (E. Gamaly, et al.). 6. Cross-beam PLD: Metastable Film Structures from Intersecting Plumes (A. Gorbunoff). 7. Combinatorial Pulsed Laser Deposition (I. Takeuchi). 8. Growth Kinetics During Pulsed Laser Deposition (G. Rijnders & D. Blank). 9. Large Area Commercial Pulsed Laser Deposition (J. Greer). SECTION III. 10. Coating Powders for Drug Delivery Systems Using Pulsed Laser Deposition (J. Talton, et al.). 11. Transparent Conducting Oxide Films (H. Kim). 12. ZnO and ZnO-related Compounds (J. Perriere, et al.). 13. Group III Nitride Growth (D. O'Mahony & J. Lunney). 14. Pulsed Laser Deposition of High-Temperature Superconducting Thin Films and Their Applications (B. Schey). 15. DLC: Medical and Mechanical Applications (R. Narayan). 16. Pulsed Laser Deposition of Metals (H. Krebs). SECTION IV. 17. Optical Waveguide Growth and Applications (R. Eason, et al.). 18. Biomaterials: New issues and Breakthroughs for Biomedical Applications (V. Nelea, et al.). 19. Thermoelectric Materials (A. Dauscher & B. Lenoir). 20. Piezoelectrics (F. Cracium & M. Dinescu). 21. Ferroelectric Thin Films for Microwave Device Applications (C. Chen & J. Horwitz). 22. Films for Electrochemical Applications (M. Montenegro & T. Lippert). 23. Pulsed Laser Deposition of Tribological Coatings (A. Voevodin, et al.). SECTION V. 24. Laser Ablation Synthesis of Single-wall Carbon Nanotubes: The SLS Model (A. Gorbunoff & O. Jost). 25. Quasicrystalline Thin Films (P. Willmott).
TL;DR: The morphology of the alpha-Fe2O3 was strongly influenced by the silicon doping, decreasing the feature size of the mesoscopic film, and the best performing photoanode would yield a solar-to-chemical conversion efficiency of 2.1% in a tandem device using two dye-sensitized solar cells in series.
Abstract: Thin, silicon-doped nanocrystalline α-Fe2O3 films have been deposited on F-doped SnO2 substrates by ultrasonic spray pyrolysis and chemical vapor deposition at atmospheric pressure. The photocatalytic activity of these films with regard to photoelectrochemical water oxidation was measured at pH 13.6 under simulated AM 1.5 global sunlight. The photoanodes prepared by USP and APCVD gave 1.17 and 1.45 mA/cm2, respectively, at 1.23 V vs RHE. The morphology of the α-Fe2O3 was strongly influenced by the silicon doping, decreasing the feature size of the mesoscopic film. The silicon-doped α-Fe2O3 nano-leaflets show a preferred orientation with the (001) basal plane normal to the substrate. The best performing photoanode would yield a solar-to-chemical conversion efficiency of 2.1% in a tandem device using two dye-sensitized solar cells in series.
TL;DR: In this paper, the authors used X-ray diffraction rocking curves to provide direct evidence for highly oriented crystals at the critical buried interface between the polymer and the dielectric where the current flows in thin-film transistors.
Abstract: Thin films of polymer semiconductors are being intensively investigated for large-area electronics applications such as light-emitting diodes, photovoltaic cells and thin-film transistors. Understanding the relationship between film morphology and charge transport is key to improving the performance of thin-film transistors. Here we use X-ray diffraction rocking curves to provide direct evidence for highly oriented crystals at the critical buried interface between the polymer and the dielectric where the current flows in thin-film transistors. Treating the substrate surface with self-assembled monolayers significantly varies the concentration of these crystals. We show that the polymer morphology at the buried interface can be different from that in the bulk of the thin films, and provide insight into the processes that limit charge transport in polythiophene films. These results are used to build a more complete model of the relationship between chain packing in polymer thin-films and charge transport.
TL;DR: The construction and performance of dye-sensitized solar cells (DSCs) based on arrays of ZnO nanowires coated with thin shells of amorphous Al(2)O(3) or anatase TiO( 2) by atomic layer deposition is described and it is found that alumina shells of all thicknesses act as insulating barriers that improve cell open-circuit voltage (V(OC) and fill factor with little current falloff.
Abstract: We describe the construction and performance of dye-sensitized solar cells (DSCs) based on arrays of ZnO nanowires coated with thin shells of amorphous Al2O3 or anatase TiO2 by atomic layer deposition. We find that alumina shells of all thicknesses act as insulating barriers that improve cell open-circuit voltage (VOC) only at the expense of a larger decrease in short-circuit current density (JSC). However, titania shells 10−25 nm in thickness cause a dramatic increase in VOC and fill factor with little current falloff, resulting in a substantial improvement in overall conversion efficiency, up to 2.25% under 100 mW cm-2 AM 1.5 simulated sunlight. The superior performance of the ZnO−TiO2 core−shell nanowire cells is a result of a radial surface field within each nanowire that decreases the rate of recombination in these devices. In a related set of experiments, we have found that TiO2 blocking layers deposited underneath the nanowire films yield cells with reduced efficiency, in contrast to the beneficial...
TL;DR: The gas experiments presented confirm good sensing properties, the possibility to use dopants and catalyser such in thin film gas sensors and the real integration in low power consumption transducers of single crystalline nanobelts prove the feasibility of large scale manufacturing of well-organized sensor arrays based on different nanostructures.
TL;DR: A range of film morphologies based on the film deposition conditions are presented here to establish an optimized method of APTES film formation.
Abstract: Thin films of 3-aminopropyltriethoxysilane (APTES) are commonly used to promote adhesion between silica substrates and organic or metallic materials with applications ranging from advanced composites to biomolecular lab-on-a-chip. Unfortunately, there is confusion as to which reaction conditions will result in consistently aminated surfaces. A wide range of conflicting experimental methods are used with researchers often assuming the creation of smooth self-assembled monolayers. A range of film morphologies based on the film deposition conditions are presented here to establish an optimized method of APTES film formation. The effect of reaction temperature, solution concentration, and reaction time on the structure and morphology was studied for the system of APTES on silica. Three basic morphologies were observed: smooth thin film, smooth thick film, and roughened thick film.
TL;DR: In this article, the authors proposed to use a layer-by-layer (LbL) deposition of oppositely charged species (polyelectrolytes, nanoparticles, enzymes, dendrimers) from their solutions on the substrate surface to prepare reservoirs with regulated storage/release properties assembled with nanometer-thickness precision.
Abstract: The corrosion of metals is one of the main destructive processes that leads to huge economic losses. Polymer coating systems are normally applied on a metal surface to provide a dense barrier against the corrosive species in order to protect metal structures from corrosive attack. When the barrier is damaged and the corrosive agents penetrate to the metal surface the coating system can not stop the corrosion process. The most effective solution so far for designing anticorrosion coatings for active protection of metals is to employ chromate-containing conversion coatings. However, hexavalent chromium species are responsible for several diseases, including DNA damage and cancer, which is the main reason for banning Cr-containing anticorrosion coatings in Europe from 2007. The deposition of thin inorganic or hybrid films on metallic surfaces has been suggested as a pretreatment to provide an additional barrier against the corrosion species and mainly to improve adhesion between the metal and polymer coating system. The films are usually deposited by the plasma polymerization technique or the sol–gel route. Sol–gel-derived thin films that contain either inorganic (phosphates, vanadates, borates, and cerium and molybdenum compounds) or organic (phenylphosphonic acid, mercaptobenzothiazole, mercaptobenzoimidazole, triazole) inhibitors are investigated as substitutes for chromates. Among them, the highest activity is shown for sol–gel coatings with a cerium dopant of a critical concentration in the 0.2–0.6 wt % range. However, the negative effect of the free inhibitor occluded in the sol–gel matrix on the stability of the protective film is observed for all types of inhibitors (for instance, a higher concentration of Ce leads to the formation of microholes in the sol–gel film). This shortcoming calls for the development of nanometer-scale reservoirs to isolate an inhibitor inside and prevent its direct interaction with the sol–gel matrix. Nanoreservoirs should be homogeneously distributed in the film matrix and should possess controlled and corrosion-stimulated inhibitor release to cure corrosion defects. Mixed-oxide nanoparticles (e.g. ZrO2/CeO2), [4] b-cyclodextrin-inhibitor complexes, hollow polypropylene fibers, and conducting polyaniline have been explored as prospective reservoirs for corrosion inhibitors to be incorporated in the protective film. The common mechanism of the nanoreservoir activity is based on the slow release of inhibitor triggered by corrosion processes. Ion exchangers have also been investigated as ‘smart’ reservoirs for corrosion inhibitors. Chemically synthesized hydrocalmite behaves as an anion exchanger: adsorbing corrosive chloride ions and releasing corrosion-inhibiting nitrite anions. Despite considerable efforts devoted to the development of new, complex anticorrosion systems, practically no single solution is able to fulfill the requirements of sufficient corrosion protection while avoiding chromates in the coating, especially in the case of aluminum alloys used for aerospace applications. The recently developed technology of layer-by-layer (LbL) deposition of oppositely charged species (polyelectrolytes, nanoparticles, enzymes, dendrimers) from their solutions on the substrate surface represents an interesting approach to prepare reservoirs with regulated storage/release properties assembled with nanometer-thickness precision. LbL coatings are of practical interest in photonics (optical filters, luminescent coatings), electrocatalysis (electrodes for DNA transfer, enzyme-catalyzed oxidation), as membranes, and chemical reactors. LbL-assembled polyelectrolyte multilayers reveal controlled permeability properties. Depending on the nature of the assembled monolayers, the permeability of multilayer films can be controlled by changing pH, ionic strength, and temperature, or by applying magnetic or electromagnetic fields. Polyelectrolyte assemblies have never been used in corrosion-protection coatings, although storage of corrosion inhibitors in polyelectrolyte multilayers can confer several advantages: they can prevent a negative effect of the corrosion inhibitor on the stability of the coating, decrease the influence of the coating polymerization on the inhibitor, and provide intelligent release of the corrosion inhibitor, as the permeability C O M M U N IC A TI O N S
TL;DR: All-nanoparticle thin-film coatings that exhibit antireflection, antifogging, and self-cleaning properties have been prepared via layer-by-layer deposition of TiO( 2) and SiO(2) nanoparticles using a simple method based on ellipsometry.
Abstract: All-nanoparticle thin-film coatings that exhibit antireflection, antifogging (superhydrophilicity), and self-cleaning properties have been prepared via layer-by-layer deposition of TiO2 and SiO2 nanoparticles. The porosity and chemical composition of the coatings were determined using a simple method that is based on ellipsometry and does not require any assumptions about the refractive indices of the constituent nanoparticles. The presence of nanopores in the TiO2/SiO2 nanoparticle coatings results in superhydrophilicity as well as antireflection properties. The superhydrophilicity of contaminated coatings could also be readily recovered and retained after ultraviolet irradiation.
TL;DR: In this paper, a silicon thin-film electrode (thickness = 200nm) is prepared by E-beam evaporation and deposition on copper foil, and the electrochemical performance of a lithium/silicon thinfilm cell is investigated in ethylene carbonate/diethyl carbonate 1.3m LiPF 6 with and without 3.5% fluoroethylene carbonate (FEC).
TL;DR: The introduction of the alkoxystyryl group extends the conjugation of the bipyridine donor ligand increasing markedly their molar extinction coefficient and solar light harvesting capacity and the high extinction coefficients of these sensitizers enable realization of a new generation of a thin film dye sensitized solar cell (DSC) yielding high conversion efficiency at full sunlight even with viscous electrolytes based on ionic liquids or nonvolatile solvents.
Abstract: Two novel heteroleptic sensitizers, Ru((4,4-dicarboxylic acid-2,2‘-bipyridine)(4,4‘-bis(p-hexyloxystyryl)-2,2-bipyridine)(NCS)2 and Ru((4,4-dicarboxylic acid-2,2‘-bipyridine)(4,4‘-bis(p-methoxystyryl)-2,2‘-bipyridine) (NCS)2, coded as K-19 and K-73, respectively, have been synthesized and characterized by 1H NMR, FTIR, UV−vis absorption, and emission spectroscopy and excited-state lifetime and spectroelectrochemical measurements. The introduction of the alkoxystyryl group extends the conjugation of the bipyridine donor ligand increasing markedly their molar extinction coefficient and solar light harvesting capacity. The dynamics of photoinduced charge separation following electronic excitation of the K-19 dye was scrutinized by time-resolved laser spectroscopy. The electron transfer from K-19 to the conduction band of TiO2 is completed within 20 fs while charge recombination has a half-life time of 800 μs. The high extinction coefficients of these sensitizers enable realization of a new generation of a th...
TL;DR: It is suggested that the superhydrophilic behavior is driven by the rapid infiltration of water into a 3D nanoporous network created under specific assembly conditions.
Abstract: Multifunctional nanoporous thin films have been fabricated from layer-by-layer assembled silica nanoparticles and a polycation. The resultant multilayer films were found to exhibit both antifogging and antireflection properties. The antifogging properties are a direct result of the development of superhydrophilic wetting characteristics (water droplet contact angle <5° within 0.5 s or less). The nearly instantaneous sheetlike wetting promoted by the superhydrophilic multilayer prevents light scattering water droplets from forming on a surface. The low refractive index of the multilayer film (as low as 1.22) resulting from the presence of nanopores was found to impart excellent antireflection properties. Glass slides coated on both sides with a nanoporous multilayer film exhibited transmission levels as high as 99.8%. Stable superhydrophilic wetting characteristics were obtained only after a critical number of bilayers were deposited onto a surface. The assembly conditions (solution pH and nanoparticle con...
TL;DR: In this article, a polycrystalline thin films of tin sulphide have been synthesized using spray pyrolysis, which had resistivities ∼30 cm with an optical energy band gap (E g ) of 1.32 eV.
TL;DR: In this paper, an increase of 80% increase in current density was observed due to the inclusion of scattering layers in dye-sensitized solar cells (DSSCs), and an additional light scattering layer (consisting of TiO 2 -Rutile and ZrO 2 in a ratio of 1:3) was employed to study the optical properties of these scattering layers.
15 Sep 2006
TL;DR: In this paper, the authors present a characterization of thin-film crystalline Si solar cells on low-cost Si carriers, and present a model for charge carrier photogeneration in doped and blended organic semiconductors.
Abstract: Series Preface. Preface. 1. Epitaxial thin-film crystalline Si solar cells on low-cost Si carriers (Jef Poortmans). 2.Crystalline Silicon Thin-Film Solar Cells on Foreign Substrates by High-Temperature Deposition and Recrystallization (Stefan Reber and Thomas Kieliba). 3. Thin-film polycrystalline Si solar cells (Guy Beaucarne and Abdellilah Slaoui). 4. Advances in microcrystalline silicon solar cell technologies (Evelyne Vallat-Sauvain, Arvind Shah and Julien Bailat). 5. Advanced Amorphous Silicon Solar Cell Technologies (Miro Zeman). 6. Chalcopyrite Based Solar Cells (Martha Ch. Lux-Steiner). 7. CdTe Thin Film Solar Cells: Characterization, Fabrication and Modelling (Marc Burgelman). 8.Charge carrier photogeneration in doped and blended organicSemiconductors (V. I. Arkhipov and H. Bassler). 9. Nanocrystalline Injection Solar Cells (Michael Gratzel). 10. Charge Transport and Recombination in Donor-Acceptor Bulk Heterojunction Solar Cells (A. J. Mozer and N. S. Sariciftci). 11. The Terawatt Challenge for Thin Film PV (Ken Zweibel).