Showing papers by "Claes-Göran Granqvist published in 2010"
TL;DR: In this article, it was shown that dilute composites with VO2 nanoparticles embedded in hosts with properties mimicking glass or polymer can yield significantly decreased luminous absorption jointly with much enhanced transmittance modulation of solar energy.
Abstract: VO2-based films are thermochromic and show infrared reflectance above a “critical” temperature in the vicinity of room temperature. Implementations on energy efficient windows have been discussed for decades but have been severely curtailed since the luminous absorptance is undesirably large and the solar energy transmittance modulation is too small. Here we show by calculations based on effective medium theory that dilute composites with VO2 nanoparticles embedded in hosts with properties mimicking glass or polymer can yield significantly decreased luminous absorption jointly with much enhanced transmittance modulation of solar energy. These results demonstrate that VO2-based nanothermochromics opens new avenues toward energy efficient fenestration.
273 citations
Book•
29 Sep 2010
TL;DR: Green Nanotechnology: Introduction and Invitation What is Nanotechnology? What is green nanotechnology? Some Basic Issues in Nanoscience Nanoscopy, Dimensionality, and Thin Films Outdoing Nature in Exploiting Complexity Energy Supply and Demand Energy and Development References In Harmony with the Environment: Nature's Energy Flows and Desired Materials Properties Global Energy Flowing Radiation in Our Ambience: An Overview Interaction Between Radiation and Materials Beam and Diffuse Radiation Hemispherical Absorptance Solar and Daylighting Performance Parameters Thermal Radiation and Spectral Properties of the Atmosphere
Abstract: Green Nanotechnology: Introduction and Invitation What Is Nanotechnology? What Is Green Nanotechnology? Some Basic Issues in Nanoscience Nanoscience, Dimensionality, and Thin Films Outdoing Nature in Exploiting Complexity Energy Supply and Demand Energy and Development References In Harmony with the Environment: Nature's Energy Flows and Desired Materials Properties Global Energy Flows Radiation in Our Ambience: An Overview Interaction Between Radiation and Materials Beam and Diffuse Radiation Hemispherical Absorptance Solar and Daylighting Performance Parameters Thermal Radiation and Spectral Properties of the Atmosphere Dynamical Environmental Properties Materials for Optimized Use of the Spectral, Directional, and Dynamical Properties of Solar Energy and Sky Radiation Thermal and Density Gradients in the Atmosphere and Oceans Performance of Energy Systems: Thermodynamics and Value References Optical Materials Science for Green Nanotechnology: The Basics Light and Nanostructures Spectral Properties of Uniform Materials Plasmonic Materials in General Materials for Electron-Based Plasmonics: Mirrors for Visible and Infrared Light Ionic-Based Materials with Narrow-Band Infrared Properties Generic Classes of Spectrally Selective Materials Thin Films for Controlling Spectral Properties and Local Light Intensities Nanoparticle Optics Optical Homogenization of Nanocomposites Surface Plasmon Resonances in Films, Particles, and "Rectennas" Temporary "Storage" of Light at Resonances and in Evanescent Fields References Visual Indoors-Outdoors Contact and Daylighting: Windows General Introduction Spectral Selectivity: The Potential in Energy Efficiency Spectral Selectivity of Noble-Metal-Based Films Spectral Selectivity of Oxide-Semiconductor-Based Films Spectral Selectivity: Novel Developments for Films and Foils Optimized Angular Properties: The Energy Efficiency That Is Possible Angular Selectivity of Films with Inclined Columnar Nanostructures Chromogenics: The Energy Efficiency That Is Possible Photochromics Thermochromics Electrochromics References Electric Lighting and Daylighting: Luminaires Lighting: Past, Present, and Future Daylighting Technology: The "Cool" Option Dielectric Mirrors Based on Nanostructure Luminescent Solar Concentrators for Daylighting and Solar Power Light Diffusing Transmitting Materials Advanced Electronic Lighting Concepts References Heat and Electricity: Solar Collectors and Solar Cells Solar Thermal Materials and Devices Photovoltaic Materials and Devices References Coolness: High-Albedo Surfaces and Sky Cooling Devices Two Cooling Strategies City Heating, Global Cooling, and Summer Blackouts High-Albedo Paints for Cool Buildings Sky Cooling to Subambient Temperatures Water Condensation Using Sky Cooling A Role for Cooling and Waste Heat in Electric Power Generation Electronic Cooling and Nanotechnology Whither Cooling? References Supporting Nanotechnologies: Air Sensing and Cleaning, Thermal Insulation and Electrical Storage Air Quality and Air Sensing Photocatalysis for Cleaning Thermal Insulation with Nanomaterials Green Energy Storage References Conclusions: Nanotechnologies for a Sustainable Future Energy and the Future New Technologies and Growing Uptake of Proven Technologies Towards a "Nanoworld" References Appendix 1: Thin Film Deposition Appendix 2: Abbreviations, Acronyms, and Symbols Index
181 citations
TL;DR: In this paper, the authors summarize recent work on thermochromic VO 2 -based thin films with particular attention to multi-layer of VO 2 and TiO 2 and new VO 2 :Mg films for which the doping gives significantly lowered absorption of visible light.
177 citations
TL;DR: In this paper, Tungsten oxide and nickel oxide were made by reactive dc magnetron sputtering and were characterized by X-ray diffraction, Rutherford backscattering spectrometry, scanning e...
91 citations
TL;DR: In this article, a dual-target reactive DC magnetron sputtering in an Ar+O 2 plasma was used to create transparent and conducting thin films of TiO 2 :Nb on glass and aluminum substrates.
40 citations
TL;DR: In this article, two equivalent circuit models were compared for the bulk impedance response for polyethyleneimine and different concentrations of lithium bis(trifluoromethylsulfonyl) imide at different temperatures.
Abstract: Polymer electrolytes containing polyethyleneimine and different concentrations of lithium bis(trifluoromethylsulfonyl) imide were investigated by impedance spectroscopy at different temperatures. Two equivalent circuit models were compared for the bulk impedance response. The first one includes a conductive Havriliak–Negami (HN) element which represents ionic conductivity and ion pair relaxation in a single process, and the second model includes a dielectric HN element, which represents ion pair relaxation, in parallel with ion conductivity. Comparison of the two circuit models showed that the quality of the fit was similar and in some cases better for the conductive model. The experimental data follow the Barton–Nakajima–Namikawa relation, which relates the ion conductivity and the parameters of the relaxation. This indicates that ion conductivity and ion pair relaxation are two parts of the same process and should be described by the conductive model.
31 citations
TL;DR: In this article, the glass transition temperature (Tg) and viscosity of PEI-LiTFSI electrolytes have minima at a [N]:[Li] ratio of 100:1.
25 citations
TL;DR: In this paper, a method for characterization of ageing of electrochromic materials by electrochemical impedance spectroscopy (EIS) was developed, in which a very small amount of optical degradation was observed in both the bleached and coloured states.
Abstract: We have developed a method for characterization of ageing of electrochromic materials by electrochemical impedance spectroscopy (EIS). Electrochromic WO3 thin films have been electrochemically cycled in propionic acid electrolyte and probed by EIS and optical measurements. A very small amount of optical degradation was observed in both the bleached and coloured states. The samples exhibited a few hundred times higher impedance in the bleached state than in the coloured state. It was observed that, in the bleached state, impedance values at low frequencies increased significantly with increasing number of cycles.
12 citations
01 Jan 2010
TL;DR: In this paper, the transmittance of visible light and solar energy to be varied between widely separated extrema was investigated in the context of electrochromic devices, which have large potential applications for energy efficient a...
Abstract: Electrochromic devices allow the transmittance of visible light and solar energy to be varied between widely separated extrema. Such devices have large potential applications for energy efficient a ...
6 citations
TL;DR: In this article, the limitations of thermochromic VO2 films for energy efficient fenestration and showed from calculations that nanocomposites containing VO2 can have superior properties and display high luminous transmittance and large temperature-dependent solar transmittances modulation.
Abstract: Chromogenic materials are able to change their optical properties in response to external stimuli such as temperature (in thermochromic materials) and electrical charge insertion (in electrochromic materials). Below we review some recent advances for these types of materials. Specifically we first discuss the limitations of thermochromic VO2 films for energy efficient fenestration and show from calculations that nanocomposites containing VO2 can have superior properties and display high luminous transmittance and large temperature-dependent solar transmittance modulation. Even better results may be found for nanoparticles of VO2:Mg. In the second part of the paper we survey some recent progress for electrochromic devices and show that W oxide films have increased coloration efficiency when some Ni oxide is added. We also present initial results for flexible electrochromic foils produced by roll-to-roll coating and continuous lamination.
TL;DR: In this paper, the authors outline the methods by which submissions should be made to Solar Energy Materials and Solar Cells, and to clarify those research directions that the editors feel need special attention, and they encourage all innovative approaches in materials science and engineering as it applies to the field of solar energy, especially those approaches that use analytical tools applied towards an understanding of underlying chemistry, physics, and interface properties.
29 Sep 2010
TL;DR: In this paper, it was shown that the SnO2:In films were considerably rougher than the glass itself, and this roughness influenced the Au film formation so that large scale coalescence set in at a somewhat larger thickness for films on SnO 2:In than on glass.
Abstract: Thin films of Au were made by sputter deposition onto glass substrates with and without transparent and electrically conducting layers of SnO2:In. The Au films were up to ~11 nm in thickness and covered the range for thin film growth from discrete islands, via large scale coalescence and formation of a meandering conducting network, to the formation of a more or less “holey” film. Scanning electron microscopy and atomic force microscopy showed that the SnO2:In films were considerably rougher than the glass itself. This roughness influenced the Au film formation so that large scale coalescence set in at a somewhat larger thickness for films on SnO2:In than on glass. Measurements of spectral optical transmittance and electrical resistance could be reconciled with impeded Au film formation on the SnO2:In layer, leading to pronounced “plateaus” in the near infrared optical properties for Au films on SnO2:In and an accompanying change from such two-layer films having a lower resistance than the single gold film at thicknesses below large scale coalescence to the opposite behavior for larger film thicknesses.
29 Sep 2010
29 Sep 2010