| 1. |
- Coll, M., et al.
(författare)
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Towards Oxide Electronics: a Roadmap
- 2019
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Ingår i: Applied Surface Science. - : Elsevier BV. - 0169-4332 .- 1873-5584. ; 482, s. 1-93
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Tidskriftsartikel (refereegranskat)abstract
- At the end of a rush lasting over half a century, in which CMOS technology has been experiencing a constant and breathtaking increase of device speed and density, Moore’s law is approaching the insurmountable barrier given by the ultimate atomic nature of matter. A major challenge for 21st century scientists is finding novel strategies, concepts and materials for replacing silicon-based CMOS semiconductor technologies and guaranteeing a continued and steady technological progress in next decades. Among the materials classes candidate to contribute to this momentous challenge, oxide films and heterostructures are a particularly appealing hunting ground. The vastity, intended in pure chemical terms, of this class of compounds, the complexity of their correlated behaviour, and the wealth of functional properties they display, has already made these systems the subject of choice, worldwide, of a strongly networked, dynamic and interdisciplinary research community. Oxide science and technology has been the target of a wide four-year project, named Towards Oxide-Based Electronics (TO-BE), that has been recently running in Europe and has involved as participants several hundred scientists from 29 EU countries. In this review and perspective paper, published as a final deliverable of the TO-BE Action, the opportunities of oxides as future electronic materials for Information and Communication Technologies ICT and Energy are discussed. The paper is organized as a set of contributions, all selected and ordered as individual building blocks of a wider general scheme. After a brief preface by the editors and an introductory contribution, two sections follow. The first is mainly devoted to providing a perspective on the latest theoretical and experimental methods that are employed to investigate oxides and to produce oxide-based films, heterostructures and devices. In the second, all contributions are dedicated to different specific fields of applications of oxide thin films and heterostructures, in sectors as data storage and computing, optics and plasmonics, magnonics, energy conversion and harvesting, and power electronics.
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| 3. |
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| 4. |
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| 5. |
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| 6. |
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| 7. |
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| 8. |
- Sorar, Idris, et al.
(författare)
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Electrochromism in Ni Oxide Thin Films Made by Advanced Gas Deposition and Sputtering : A Comparative Study Demonstrating the Significance of Surface Effects
- 2020
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Ingår i: Journal of the Electrochemical Society. - : The Electrochemical Society. - 0013-4651 .- 1945-7111. ; 167:11
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Tidskriftsartikel (refereegranskat)abstract
- Films of electrochromic Ni oxide, with thickness in the ∼100–1000-nm range, were prepared by reactive advanced gas deposition (AGD) and, for comparison, also by reactive DC magnetron sputtering (MS). Voltammetric cycling was performed in an electrolyte of lithium perchlorate in propylene carbonate in the voltage range 2.0–4.1 V vs Li/Li+, and concurrent optical transmittance modulation was studied at a wavelength of 530 nm. For the thickest films, the optical modulation range was as large as ∼54% and the maximum transmittance was ∼82% for deposition by AGD, whereas the corresponding numbers were ∼45% and ∼87% for MS. Rutherford backscattering spectrometry together with measurements of film thickness demonstrated that the porosity of 400–500-nm-thick films made by AGD and MS were ∼84% and ∼45%, respectively. The charge exchange per mass unit was as high as 48–67 C g–1 for samples made by AGD. The corresponding number was much lower for MS, namely 13–18 C g–1. These results lend convincing support to the view that the electrochromism of Ni-oxide-based films in Li-ion-conducting electrolytes is dominated by surface effects.
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| 9. |
- Aijaz, Asim, et al.
(författare)
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Low-temperature synthesis of thermochromic vanadium dioxide thin films by reactive high power impulse magnetron sputtering
- 2016
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Ingår i: Solar Energy Materials and Solar Cells. - : Elsevier BV. - 0927-0248 .- 1879-3398. ; 149, s. 137-144
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Tidskriftsartikel (refereegranskat)abstract
- Thermochromic (TC) vanadium dioxide thin films provide means for controlling solar energy throughput and can be used for energy-saving applications such as smart windows. One of the factors limiting the deployment of VO2 films in TC devices is the growth temperature tau(s). At present, temperatures in excess of 450 degrees C are required, which clearly can be an impediment especially for temperature-sensitive substrates. Here we address the issue of high tau(s) by synthesizing VO2 thin films from highly ionized fluxes of depositing species generated in high power impulse magnetron sputtering (HiPIMS) discharges. The use of ions facilitates low-temperature film growth because the energy of the depositing species can be readily manipulated by substrate bias. For comparison, films were also synthesized by pulsed direct current magnetron sputtering. Structural and optical characterization of VO2 thin films on ITO-coated glass substrates confirms previous results that HiPIMS allows tau(s) to be reduced from 500 to 300 degrees C. Importantly, we demonstrated that HiPIMS permits the composition and TC response of the films to be tuned by altering the energy of the deposition flux via substrate bias. An optimum ion energy of 100 eV was identified, which points at a potential for further reduction of tau(s) thereby opening new possibilities for industrially-relevant applications of VO2-based TC thin films. Weak TC activity was observed even at tau(s) approximate to 200 degrees C in HiPIMS-produced films.
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| 10. |
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| 11. |
- Arvizu, Miguel A, et al.
(författare)
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Rejuvenation of degraded electrochromic MoO3 thin films made by DC magnetron sputtering : Preliminary results
- 2016
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Ingår i: Journal of Physics: Conference Series. - : Institute of Physics Publishing (IOPP).
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Konferensbidrag (refereegranskat)abstract
- Molybdenum oxide thin films were deposited by reactive DC magnetron sputtering and were subjected to voltammetric cycling in an electrolyte comprised of lithium perchlorate in propylene carbonate. The films were heavily degraded during 20 voltammetric cycles in an extended voltage range. The films were subsequently rejuvenated by use of potentiostatic treatments under different voltages during 20 hours. Optical changes were recorded during the electrochemical degradation and ensuing rejuvenation.
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| 12. |
- Atak, Gamze, et al.
(författare)
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Cycling durability and potentiostatic rejuvenation of electrochromic tungsten oxide thin films : Effect of silica nanoparticles in LiClO4-Propylene carbonate electrolytes
- 2023
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Ingår i: Solar Energy Materials and Solar Cells. - : Elsevier. - 0927-0248 .- 1879-3398. ; 250
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Tidskriftsartikel (refereegranskat)abstract
- Electrochromic (EC) technology allows control of the transmission of visible light and solar radiation through thin-film devices. When applied to “smart” windows, EC technology can significantly diminish energy use for cooling and air conditioning of buildings and simultaneously provide good indoor comfort for the buildings’ occupants through reduced glare. EC “smart” windows are available on the market, but it is nevertheless important that their degradation under operating conditions be better understood and, ideally, prevented. In the present work, we investigated EC properties, voltammetric cycling durability, and potentiostatic rejuvenation of sputter-deposited WO3 thin films immersed in LiClO4–propylene carbonate electrolytes containing up to 3.0 wt% of ∼7-nm-diameter SiO2 nanoparticles. Adding about 1 wt% SiO2 led to a significant improvement in cycling durability in the commonly used potential range of 2.0–4.0 V vs. Li/Li+. Furthermore, X-ray photoemission spectroscopy indicated that O–Si bonds were associated with enhanced durability in the presence of SiO2 nanoparticles.
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| 13. |
- Atak, Gamze, et al.
(författare)
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Electrochromic performance of WO3 films with different ITO layers
- 2019
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Ingår i: EMRS Spring Meeting 2019..
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Electrochromic (EC) materials are able to change their optical properties such as transmission, absorption and reflection reversibly by application of an external voltage. EC metal oxides are divided into two groups: cathodic (coloring under ion insertion) and anodic (coloring under ion extraction). Tungsten oxide (WO3) is a well-known cathodic EC material and has been intensively studied in the last 30 years. EC materials and devices have been developed as an alternative to passive coating materials for light and heat management. Conventionally, an EC device is a construction with five-layers: transparent conducting oxide (TCO)/cathodic EC/ion conducting layer (liquid, gel or solid)/anodic EC/TCO, either all on one substrate or positioned between two substrates in a laminated configuration. Indium-tin oxide (ITO) coated substrates are used as a TCO electrode in EC applications due to their high conductivity and transparency.In this study, we deposited WO3 films onto ITO coated glass substrates with different sheet resistances (15, 30, 60 and 1000 Ω/□) by using DC magnetron sputtering technique. Optical and structural properties of ITO films were investigated. For durability studies, cyclic voltammetry data was recorded for up to 500 cycles between 2.0 and 4.0 V versus Li/Li+ at a scan rate of 20 mV s−1. Chronoamperometry measurements of the WO3 films were also performed. We measured the inserted and extracted charges as well as bleaching and coloring times of WO3 films with different ITO layer properties. Generally, ITO with low resistivity is preferred for the electrochemical measurements while absorption is low in the near-infrared region for ITO with higher resistivity. In this study, it is observed that the ITO with 60 Ω/□ sheet resistance is very suitable for optical and electrochromic measurements.
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| 14. |
- Atak, Gamze, et al.
(författare)
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Electrochromism of nitrogen-doped tungsten oxide thin films
- 2020
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Ingår i: Materials Today. - : Elsevier BV. - 2214-7853. ; 33:6, s. 2434-2439
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Tidskriftsartikel (refereegranskat)abstract
- Tungsten-oxide-based thin films were prepared by reactive DC magnetron sputtering in the presence ofoxygen and nitrogen. Nitrogen contents up to 12 at.% were documented by Rutherford backscattering spectrometry and time-of-flight elastic recoil detection analysis. Optical and electrochemical measurements showed that films with up to 4 at.% of nitrogen were as transparent as undoped tungsten oxide films and displayed enhanced electrochromic properties manifested in an increase in the coloration efficiency by as much as 20%.
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| 15. |
- Avendano, Esteban, et al.
(författare)
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Coloration Mechanism in Proton-Intercalated Electrochromic Hydrated NiOy and Ni1-xVxOy Thin Films
- 2009
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Ingår i: Journal of the Electrochemical Society. - : The Electrochemical Society. - 0013-4651 .- 1945-7111. ; 156:8, s. p132-p138
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Tidskriftsartikel (refereegranskat)abstract
- Electrochromic (EC) films of nickel oxide, with and without vanadium, were prepared by reactive dc magnetron sputtering. They were characterized by electrochemical and optical measurements and studied by X-ray photoelectron spectroscopy (PES) using synchrotron radiation. The films were analyzed under as-deposited conditions and after bleaching/coloration by insertion/extraction of protons from a basic solution and ensuing charge stabilization. Optical measurements were consistent with a coloration process due to charge-transfer transitions from Ni2+ to Ni3+ states. The PES measurements showed a higher concentration of Ni3+ in the colored films. Moreover, two peaks were present in the O 1s spectra of the bleached film and pointed to contributions of Ni(OH)(2) and NiO. The changes in the O 1s spectra upon coloration treatment indicate the presence of Ni2O3 in the colored film and necessitated an extension of the conventional model for the mechanism of EC coloration. The model involves not only proton extraction from nickel hydroxide to form nickel oxyhydroxide but also participation of NiO in the coloration process to form Ni2O3.
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| 16. |
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| 17. |
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| 18. |
- Bayrak Pehlivan, Ilknur, et al.
(författare)
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[PEI-SiO2]:[LiTFSI] nanocomposite polymer electrolytes : Ion conduction and optical properties
- 2012
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Ingår i: Solar Energy Materials and Solar Cells. - : Elsevier BV. - 0927-0248 .- 1879-3398. ; 98, s. 465-471
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Tidskriftsartikel (refereegranskat)abstract
- Ion conductivity and optical properties were investigated for polymer electrolytes based on poly (ethyleneimine) and lithium bis(trifluoromethylsulfonyl)imide and also containing up to 9 wt.% of 7-nm-diameter SiO2 nanoparticles. The [N]:[Li] molar ratio was kept constant at 50:1. Impedance measurements were performed in the frequency range 10(-2)-10(7) Hz and between the temperatures 20 and 70 degrees C with an applied ac voltage of 1 V. Spectrophotometric data of total and diffuse transmittance were taken between the wavelengths 300 and 2500 nm. The bulk impedance was fitted to a conductive Havriliak-Negami circuit model. The ion conductivity increased monotonically for increasing SiO2 contents: specifically its room temperature value went from 8.5 x 10(-7) S/cm without nanoparticles to 3.8 x 10(-5) S/cm for 8 wt.% of SiO2 while the diffuse transmittance remained at similar to 1% so that optical clarity prevailed.
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| 19. |
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| 20. |
- Chen, Hsien-Pu, et al.
(författare)
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On The "Cracking" Scheme in The Paper "A Directional Coupler Attack Against the Kish Key Distribution System" by Gunn, Allison And Abbott
- 2014
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Ingår i: METROLOGY AND MEASUREMENT SYSTEMS. - : Polish Academy of Sciences Chancellery. - 0860-8229 .- 2300-1941. ; 21:3, s. 389-400
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Tidskriftsartikel (refereegranskat)abstract
- Recently, Gunn, Allison and Abbott (GAA) [http://arxiv.org/pdf/1402.2709v2.pdf] proposed a new scheme to utilize electromagnetic waves for eavesdropping on the Kirchhoff-law-Johnson-noise (KLJN) secure key distribution. We proved in a former paper [Fluct. Noise Lett. 13 (2014) 1450016] that GAA's mathematical model is unphysical. Here we analyze GAA's cracking scheme and show that, in the case of a loss-free cable, it provides less eavesdropping information than in the earlier (Bergou)-Scheuer-Yariv mean-square-based attack [Kish LB, Scheuer J, Phys. Lett. A 374:2140-2142 (2010)], while it offers no information in the case of a lossy cable. We also investigate GAA's claim to be experimentally capable of distinguishing-using statistics over a few correlation times only-the distributions of two Gaussian noises with a relative variance difference of less than 10(-8). Normally such distinctions would require hundreds of millions of correlations times to be observable. We identify several potential experimental artifacts as results of poor KLJN design, which can lead to GAA's assertions: deterministic currents due to spurious harmonic components caused by ground loops, DC offset, aliasing, non-Gaussian features including non-linearities and other non-idealities in generators, and the time-derivative nature of GAA's scheme which tends to enhance all of these artifacts.
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| 21. |
- Cindemir, Umut, et al.
(författare)
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Nickel oxide thin film sensor for fluctuation-enhanced gas sensing of formaldehyde
- 2015
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Ingår i: 2015 IEEE Sensors. - 9781479982035
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Konferensbidrag (refereegranskat)abstract
- Nanocrystalline nickel-oxide-based thin films were prepared by advanced reactive gas deposition, and the response of these films to formaldehyde was studied by fluctuation-enhanced sensing. Morphological and structural analyses showed porous deposits of nickel oxide particles with face-centered cubic structure. Resistance fluctuations were measured upon exposure to ethanol, formaldehyde and methane at 200 degrees C. Power density spectra were used to quantify the response. The response to formaldehyde was higher than to ethanol at 200 degrees C, and no significant response was observed for methane thus demonstrating some gas-species selectivity.
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| 22. |
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| 23. |
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| 24. |
- Espinosa, E. H., et al.
(författare)
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Highly Selective NO2 Gas Sensors made of MWCNTs and WO3 Hybrid Layers
- 2007
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Ingår i: Journal of the Electrochemical Society. - : The Electrochemical Society. - 0013-4651 .- 1945-7111. ; 154:5, s. J141-J149
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Tidskriftsartikel (refereegranskat)abstract
- Hybrid gas sensors were fabricated by means of multiwalled carbon nanotubes (MWCNTs) covered by W O3 deposited by an advanced reactive gas deposition method. In order to increase the dispersion of nanotubes and attach functional groups to their surface so as to enhance their compatibility with other compounds, the MWCNTs were functionalized in two different radio-frequency plasmas (oxygen or hydrogen) under different operating conditions. X-ray photoelectron spectroscopy, scanning electron microscopy, and atomic force microscopy were employed to analyze the composition and morphology of the hybrid films. Gas sensors based on such films were found to be very selective to N O2 when operated at room temperature. No cross-sensitivity was found to other hazardous gases such as N H3 or CO.
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| 25. |
- Ginley, D., et al.
(författare)
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Transparent Oxides and Related Materials for Electronics and Optics : Phys. Status Solidi A
- 2019
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Ingår i: physica status solidi (a). - Weinheim : Wiley. - 1862-6300.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The International Symposium on Transparent Oxide Thin Films for Electronics and Optics (TOEO) has been held every two years since 1997. The 10th TOEO conference (TOEO‐10), whose name was changed to The International Symposium on Transparent Oxide and Related Materials for Electronics and Optics so as to include recent related material from TOEO‐8, was held July 3–5, 2017, at International Conference Center, Waseda University, Tokyo, Japan. This conference was very successful and included 105 participants. The TOEO sessions had one special panel discussion on “Energy, the global challenge”, 22 invited talks, 6 contributed oral papers, and 34 poster presentations.We are pleased to publish this special issue of Physica Status Solidi (a). The highest‐quality papers were selected through on‐site review at the conference and by the standard peer‐review process following the criteria of the journal. We expect that this volume will promote the research on transparent oxide materials.The organizers thank Japan Society for the Promotion of Science, the 166th Committee, for continued support.
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| 26. |
- Gómez, M.M., et al.
(författare)
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Dye-sensitized sputtered titanium oxide films for photovoltaic applications : influence of the O2/Ar gas flow ratio during the deposition
- 2003
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Ingår i: Solar Energy Materials and Solar Cells. - 0927-0248 .- 1879-3398. ; 76:1, s. 37-56
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Tidskriftsartikel (refereegranskat)abstract
- Titanium oxide films were prepared by reactive DC magnetron sputtering onto SnO2:F coated glass substrates. The O-2/Ar gas flow ratio was kept at a constant value Gamma during the deposition, and a series of films were deposited with 0.050 < Gamma < 0.072. Structural studies were performed by X-ray diffraction and transmission electron microscopy; the structure displayed penniform features with a clear dependence on F. Charge transport in the films was evaluated by use of time-resolved photocurrents; a diffusion model was fitted to the experimental data and two different transport mechanisms were proposed depending on the film stoichiometry. Dye sensitization in cis-dithiocyanato-bis(2,2'-bipyridyl-4,4'-dicarboxylate) ruthenium (II) was performed to evaluate incident photon-to-current conversion efficiency and solar cell properties of the films. These parameters showed a clear dependence on Gamma. Optical measurements gave evidence for the presence of polaron absorption for the film deposited at Gamma = 0.050.
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| 27. |
- Granqvist, Claes G., 1946-, et al.
(författare)
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Advances in electrochromic device technology : Multiple roads towards superior durability
- 2019
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Ingår i: Surface & Coatings Technology. - : Elsevier. - 0257-8972 .- 1879-3347. ; 357, s. 619-625
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Tidskriftsartikel (refereegranskat)abstract
- Most electrochromic (EC) devices must have a service lifetime of many years, and this is particularly so for “smart windows” in buildings with good energy efficiency and indoor comfort. The central part of oxide-based EC devices contains thin films based on W oxide and Ni oxide together with an interposed electrolyte. Depending on operating conditions, these films may show degradation at a slower or faster pace, and means to prevent or reverse this phenomenon, or as a minimum allow reliable lifetime prediction, have been sought ever since the beginnings of EC technology. Here we survey recent endeavors related to EC films of W oxide and Ni oxide and show that (i) electrochemical pretreatment of films in a liquid electrolyte can significantly improve durability, (ii) electrochemical posttreatment in a liquid electrolyte can rejuvenate degraded films, (iii) mixed oxides can have better durability and optical performance than corresponding pure oxides, and (iv) lifetime prediction is possible.
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| 28. |
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| 29. |
- Granqvist, Claes Göran, et al.
(författare)
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Electrochromic foil-based devices : Optical transmittance and modulation range, effect of ultravioled irradiation, and quality assessment by 1/f current noise
- 2008
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Ingår i: Thin Solid Films. - : Elsevier BV. - 0040-6090 .- 1879-2731. ; 516:17, s. 5921-5926
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Tidskriftsartikel (refereegranskat)abstract
- We introduce electrochromic (EC) technology for modulating the transmittance of visible light and solar radiation in window apertures, with focus on recent work on foil-type devices embodying sputter deposited WO3 and NiO films joined by a polymer electrolyte. The purpose of this paper is to present a number of new and preliminary results showing that (i) double-sided antireflection coatings based on dip coating can enhance the transmittance significantly, (ii) tandem foils can yield a ratio between bleached-state and colored-state transmittance exceeding fifty, (iii) solar irradiance onto the EC device can enhance its charge insertion dynamics and thereby its optical modulation, and (iv) electromagnetic noise spectroscopy may serve as quality assessment of EC devices.
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| 30. |
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| 31. |
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| 32. |
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| 33. |
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| 34. |
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| 35. |
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| 36. |
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| 37. |
- Granqvist, Claes G., et al.
(författare)
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Nanomaterials for benign indoor environments : Electrochromics for “smart windows”, sensors for air quality, and photo-catalysts for air cleaning
- 2007
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Ingår i: Solar Energy Materials and Solar Cells. - : Elsevier BV. - 0927-0248 .- 1879-3398. ; 91:4, s. 355-365
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Tidskriftsartikel (refereegranskat)abstract
- Nanomaterials can be used in a number of technologies in order to accomplish benign indoor environments. This paper takes a unified view on this problem from a solar-energy-based perspective and specifically considers electrochromics for achieving good day-lighting jointly with energy efficiency, sensors aimed at air quality assessment, and photocatalysis for air cleaning. Recent results, mainly from the authors’ laboratories, are reported for all of these areas.
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| 38. |
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| 39. |
- Granqvist, Claes G.
(författare)
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Recent progress in electrochromics and thermochromics : A brief survey
- 2016
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Ingår i: Thin Solid Films. - : Elsevier BV. - 0040-6090 .- 1879-2731. ; 614, s. 90-96
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Tidskriftsartikel (refereegranskat)abstract
- Contemporary architecture is characterized by large glazings, which are able to accomplish good indoors-outdoors contact and daylighting. However, glazings, encompassing windows and glass facades, are challenging with regard to energy efficiency and often lead to excessive solar energy ingress and to large thermal losses, which must be balanced by energy-demanding cooling or heating. Cooling, especially, has grown strongly in importance during recent years. Emerging technologies utilizing thermochromics and electrochromics allow control of the inflow of visible light and solar energy and thereby produce better energy efficiency than traditional glazings employing static solutions. Thermochromic thin films, based on vanadium dioxide, let through less solar energy at high temperature than at low temperature, whereas electrochromic devices include thin films-usually based on tungsten oxide and nickel oxide-that can change their transmittance of solar energy and visible light upon the application of a voltage. It is important that electrochromics, and to some degree thermochromics, can enhance indoor comfort and lead to better living and working conditions. The present brief review covers a number of recent advances in thermochromics and electrochromics with a view to applications in energy-efficient buildings.
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| 40. |
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| 41. |
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| 42. |
- Granqvist, Claes G
(författare)
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Solar Energy Materials
- 2006
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Ingår i: Kirk-Othmer Encyclopedia of Chemical Technology, 5th edition, Vol. 23. - : Wiley, Hoboken, USA.
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Bokkapitel (populärvet., debatt m.m.)
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| 43. |
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| 44. |
- Granqvist, Claes Göran, 1946-, et al.
(författare)
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Thermochromic Fenestration Based on VO2 : Finally a Technology of Practical Interest?
- 2016
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Ingår i: Society Of Vacuum Coaters 59th Annual Technical Conference Proceedings, 2016. - : Society of Vacuum Coaters. ; , s. 62-69
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Konferensbidrag (refereegranskat)abstract
- Vanadium-dioxide-based thermochromic thin films and nanoparticle composites can have significant transmittance for visible light, Tlum, while they are able to transmit more near-infrared solar radiation at τ < τc than at τ > τc, where τ denotes temperature and τc ≈ 68 °C. It has been understood for many years that these properties are of principle interest for energy efficient fenestration, but the technology has been slow to mature. The present paper summarizes the state of the art of VO2-based thermochromics and points at the many advances that have been made during recent years. Specifically, the paper discusses how to employ doping to adjust τc to room temperature and to increase Tlum, how to use nano materials to enhance the solar energy transmittance modulation and Tlum, and how to prepare nanoparticle composites by sputtering. A brief discussion is given on thermochromic light scattering, which is a recently discovered phenomenon.
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| 45. |
- Granqvist, Claes G.
(författare)
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Transparent conductors for solar energy and energy efficiency : a broad-brush picture
- 2009
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Ingår i: International Journal of Nanotechnology. - 1475-7435. ; 6:9, s. 785-798
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Tidskriftsartikel (refereegranskat)abstract
- Transparent conductors (TCs) have numerous and diverse applications for solar energy applications and for energy efficiency. The largest of these applications, in terms of area, arc based oil the fact that the TCs have low infrared emittance and can be used to improve the thermal properties of modern fenestration. Depending on whether the TCs arc reflecting or not in the near infrared pertinent to solar irradiation, the TCs can serve in 'solar control' or 'low-emittance' windows. Other applications rely oil the electrical conductivity of the TCs, which render them useful as current collectors in solar cells and for inserting and extracting electrical charge in electrochromic 'smart windows' capable of combining energy efficiency and indoor comfort in buildings. This paper ventures to give a broad-brush picture of TCs and discuss their properties from the perspective of the radiative properties in our ambience. This approach leads naturally to considerations of spectral seleclivity, angular selectivity, and temporal variability of TCs. The spectrally selective materials are thin films based on metals (normally silver) or wide hand gap semiconductors with heavy doping (normally based on indium, tin, or zinc). The potential importance of carbon-based TCs is emphasised. Angular dependent TCs, especially those for which the properties are governed by inclined columnar nanostructures, arc introduced. A discussion of TC-like materials with thermochromic and electrochromic properties is included, especially with regard to vanadium-dioxide-based films and electrochromic multilayer structures embracing tungsten oxide and nickel oxide.
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| 46. |
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| 47. |
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| 48. |
- Heszler, P., et al.
(författare)
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Laser-Induced Synthesis of Nanostructured Thin Films
- 2007
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Ingår i: Applied Surface Science. - : Elsevier BV. - 0169-4332 .- 1873-5584. ; 253:19, s. 8292-8299
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Tidskriftsartikel (refereegranskat)abstract
- We present a number of important characteristics of laser techniques for preparation of nanostructured thin films with foci on laser ablation (LA) and laser-assisted chemical vapor decomposition (LCVD). Size-related features and structures of the deposited layers are associated with process parameters. Whenever possible, the performance of the deposits is compared to that of films prepared by other methods (e.g., physical vapor synthesis such as gas deposition, sputtering, etc.). The LA and LCVD methods allow a wide variety of materials to be prepared. A number of promising applications emerge when one combines this versatility with the potential for making certain types of nanostructured layers. These possibilities are also discussed.
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| 49. |
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| 50. |
- Heszler, P, et al.
(författare)
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On the Selectivity of Nanostructured Semiconductor Gas Sensors
- 2007
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Ingår i: Physica status solidi. B, Basic research. - : Wiley. - 0370-1972 .- 1521-3951. ; 244:11, s. 4331-4335
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Tidskriftsartikel (refereegranskat)abstract
- Different methods are presented for improving chemical selectivity and sensitivity of semiconductor gassensors consisting of nanostructured thin films. Pure and doped WO3 nanoparticles, forming nanoporouslayers, are used as test material. The chemical selectivity is increased by applying different operating tem-peratures, using temperature modulation and pattern recognition methods, and by a fluctuation enhancedspectroscopy technique. The selectivity improvement of a fluctuation enhanced sensor is compared to thatof a classical resistive sensor.
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