| 1. |
- Brogren, M., et al.
(author)
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Hammarby Sjöstad-an interdisciplinary case study of the integration of photovoltaics in a new ecologically sustainable residential area in Stockholm
- 2003
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In: Solar Energy Materials and Solar Cells. - 0927-0248 .- 1879-3398. ; 75:3-4, s. 761-765
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Journal article (peer-reviewed)abstract
- The integration of photovoltaic (PV) systems in apartment buildings in a new residential area, Hammarby Sjöstad in Stockholm, has been studied using an interdisciplinary approach including e.g. interviews with actors and modelling of PV systems in PVSYST. Four of the ten construction companies represented in the area will install PV systems. The yearly electricity production from these systems has been estimated to be 63 MWh or equal to an electricity demand of 38 (out of 2300) households in the area. Interviews reveal that obstacles for the integration of PV in buildings are e.g. perceived expense and a lack of knowledge. The choice of PV technology is based more on economy, aesthetic appearance, and a wish to demonstrate environmental concern, than on optimal system performance. By integrating renewable energy technologies in the buildings, the construction companies will lay a ground for an ecologically sustainable living, but how these opportunities are utilised by future residents, managers, and caretakers of the buildings will be of decisive importance for the final outcome. © 2002 Elsevier Science B.V. All rights reserved.
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| 2. |
- Gómez, M.M., et al.
(author)
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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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In: Solar Energy Materials and Solar Cells. - 0927-0248 .- 1879-3398. ; 76:1, s. 37-56
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Journal article (peer-reviewed)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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| 3. |
- Rönnow, Daniel, et al.
(author)
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Surface roughness characterisation of a thin transparent dielectric-silver tandem by spectroscopic light scattering
- 1998
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In: Solar Energy Materials and Solar Cells. - 0927-0248 .- 1879-3398. ; 52:1-2, s. 37-43
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Journal article (peer-reviewed)abstract
- Spectroscopic light scattering was measured on a system of a dielectric layer on top of a thin (13 nm) silver film on a glass substrate. The analysis included both forward and backward scattering and excellent agreement between measured and modelled results was achieved. The theoretical analysis showed that the film interfaces were correlated, i.e. the substrate roughness was replicated, and that the interface roughness (root mean square) was in the nanometer range.
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| 4. |
- Veszelei, M, et al.
(author)
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Zr-Ce Oxides as Candidates for Optically Passive Counter Electrodes
- 1999
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In: Solar Energy Materials and Solar Cells. - 0927-0248 .- 1879-3398. ; 56:3-4, s. 223-230
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Journal article (peer-reviewed)abstract
- Zr-Ce oxide films with compositions from pure Zr oxide to pure Ce oxide were made by reactive DC magnetron co-sputtering. The composition and structure were determined by Rutherford backscattering and X-ray diffraction. Pure Ce oxide films have high charge capacity and are optically passive under charge insertion; they are, however, chemically unstable in an electrolyte of LiClO4 in propylene carbonate. Pure Zr oxide has practically zero charge capacity. Zr-Ce oxide films have high (above 80%) optical transmittance, high charge capacity, and good chemical stability. These films remain fully transparent irrespective of their degree of lithiation, which may be reconciled with electrons accommodating 4f states of Ce.
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| 5. |
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| 6. |
- Aijaz, Asim, et al.
(author)
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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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In: Solar Energy Materials and Solar Cells. - : Elsevier BV. - 0927-0248 .- 1879-3398. ; 149, s. 137-144
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Journal article (peer-reviewed)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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| 7. |
- Arvizu, Miguel A, et al.
(author)
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Electrochromism in sputter-deposited W-Ti oxide films : Durability enhancement due to Ti
- 2014
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In: Solar Energy Materials and Solar Cells. - : Elsevier BV. - 0927-0248 .- 1879-3398. ; 125, s. 184-189
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Journal article (peer-reviewed)abstract
- Thin films of W-Ti oxide were prepared by reactive DC magnetron sputtering and were characterized by Rutherford bathcattering spectrometry, X-ray diffraction, scanning electron microscopy and atomic force microscopy. The electrochromic properties were studied by cyclic voltammetry in an electrolyte of lithium perchlorate in propylene carbonate and by optical transmittance measurements. The addition of Ti significantly promoted the amorphous nature of the films and stabilized their electrochemical cycling performance and dynamic range for electrochromism. (C) 2014 Elsevier B.V. All rights reserved.
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| 8. |
- Atak, Gamze, et al.
(author)
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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
-
In: Solar Energy Materials and Solar Cells. - : Elsevier. - 0927-0248 .- 1879-3398. ; 250
-
Journal article (peer-reviewed)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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| 9. |
- Backholm, Jonas, et al.
(author)
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Iridium-based oxides: Recent advances in coloration mechanism, structural and morphological characterization
- 2008
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In: Solar Energy Materials and Solar Cells. - : Elsevier BV. - 0927-0248 .- 1879-3398. ; 92:2, s. 91-96
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Journal article (peer-reviewed)abstract
- Films of iridium-tantalum oxide and iridium oxide have been prepared by sputtering and studied regarding their structure and electrochemical properties. X-ray diffraction and transmission electron microscopy showed an average grain size of 3-4 nm for both films. Point energy dispersive X-ray spectrometry showed an inhomogeneous distribution of iridium and tantalum indicating that the iridium-tantalum oxide may be a mixture of small IrO2 and Ta2O5 grains, which is consistent with the determined composition IrTa1.4O5.6. X-ray photoelectron spectroscopy gave valuable information on the stabilization process of the as-deposited films involving an uptake of oxygen, and on a coloration mechanism only including protons.
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| 10. |
- Backholm, Jonas, et al.
(author)
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Optical properties of electrochromic iridium oxide and iridium-tantalum oxide thin films in different colouration states
- 2008
-
In: Solar Energy Materials and Solar Cells. - : Elsevier BV. - 0927-0248 .- 1879-3398. ; 92:11, s. 1388-1392
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Journal article (peer-reviewed)abstract
- Electrochromic iridium oxide (IrOx) and iridium-tantalum oxide (IrTaOx) thin films were prepared by sputtering. Complex refractive indices were determined for samples deposited on indium-tin oxide covered glass in different colouration states, and for as-deposited samples on sapphire and Corning glass. The refractive index was found to be practically constant for both IrOx (similar to 1.3) and IrTaOx (similar to 2). The extinction coefficient was found to vary between the coloured and bleached states with similar to 35% for IrOx and similar to 55% for IrTaOx at 660 nm. This is believed to be a result of the removal of intraband transitions within the Ir t(2g) band during bleaching.
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| 11. |
- Barrios, David, et al.
(author)
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Simulation of the thickness dependence of the optical properties of suspended particle devices
- 2015
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In: Solar Energy Materials and Solar Cells. - 0927-0248 .- 1879-3398. ; 143, s. 613-622
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Journal article (peer-reviewed)abstract
- Suspended particle devices (SPDs) constitute an electrically powered chromogenic technology, in which the active layer quickly are able to rapidly switches from a dark bluish-black dark color state to a clear greyish color appearance when an AC electric field is applied. Two-flux and four-flux models were used to derive refractive indices and extinction coefficients, as well as scattering and absorption coefficients, of the particle-containing active layer. These entities were used in model calculations to predict the direct, total and diffuse components of the transmittance andthe reflectance, together along with the color appearance and haze, as a function of the thickness of the active layer. An optimum thickness for the optical contrast of the SPD was determined in this way and was found to be in the range of 200 to 300 nm. The SPDdevices device exhibits a significant reflectance haze particularly in reflection.
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| 12. |
- Barrios, David, et al.
(author)
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Toward a quantitative model for suspended particle devices : Optical scattering and absorption coefficients
- 2013
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In: Solar Energy Materials and Solar Cells. - : Elsevier BV. - 0927-0248 .- 1879-3398. ; 111, s. 115-122
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Journal article (peer-reviewed)abstract
- Suspended particle devices (SPDs) allow rapid voltage-controlled modulation of their optical transmittance and are of interest for solar-energy-related and other applications. We investigated the spectral total and diffuse transmittance of an SPD, including its angular dependence. The optical modulation was large for visible light but almost nil in the infrared, and the devices had noticeable haze. A theoretical two-flux model was formulated and provided a quantitative description of the absorption and scattering coefficients and thereby of the detailed optical performance. This analysis gives a benchmark for assessing improvements of the SPD technology as well as for comparing it with alternative technologies for optical modulation.
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| 13. |
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| 14. |
- Bayrak Pehlivan, Ilknur, et al.
(author)
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[PEI-SiO2]:[LiTFSI] nanocomposite polymer electrolytes : Ion conduction and optical properties
- 2012
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In: Solar Energy Materials and Solar Cells. - : Elsevier BV. - 0927-0248 .- 1879-3398. ; 98, s. 465-471
-
Journal article (peer-reviewed)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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| 15. |
- Berggren, Lars, et al.
(author)
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Electrical Conductivity as a Function of Temperature in Amorphous Lithium Tungsten Oxide
- 2004
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In: Solar Energy Materials and Solar Cells. - : Elsevier BV. - 0927-0248 .- 1879-3398. ; 84:1, s. 329-336
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Journal article (peer-reviewed)abstract
- Tungsten oxide is a widely used electrochromic material for smart windows. In order to study the charge carriers involved in the electrochromic process, it is important to characterize the electrical transport in tungsten oxide. Substoichiometric amorphous tungsten oxide films were prepared by DC-magnetron sputtering. The films were electrochemically intercalated with lithium. The Li/W intercalation ratios for the tungsten oxide films were in the range 0.15–0.53. Temperature dependent resistivity measurements were performed in the temperature range 77–300 K for samples at different lithium intercalation levels. It was found that the data are consistent with the variable range hopping model.
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| 16. |
- Berggren, Lars, et al.
(author)
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Influence of sputtering conditions on the solar and luminous optical properties of amorphous LixWoy thin films
- 2005
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In: Solar Energy Materials and Solar Cells. - : Elsevier BV. - 0927-0248 .- 1879-3398. ; 85:4, s. 573-586
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Journal article (peer-reviewed)abstract
- Thin films of amorphous tungsten oxide were deposited by sputtering onto glass substrates coated by conductive indium–tin oxide. The films were sputtered at different oxygen-to-argon flow ratios with different pressure and power. Elastic recoil detection analysis determined the density and the stoichiometry. X-ray diffraction measurements showed that the films were amorphous. The films were electrochemically intercalated with lithium ions. At several intercalation levels of each film, the optical reflectance and transmittance were measured in the wavelength range 0.3–2.5 μm. We study the effect of various sputtering conditions on the coloration efficiency of the films and on the luminous and solar optical properties. The O2/Ar ratio and the sputter pressure determine to a large extent the optical absorption. As-deposited sputtered tungsten oxide with sufficiently little oxygen exhibits an absorption peak similar to the case of lithium intercalation.
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| 17. |
- Bergqvist, Jonas, et al.
(author)
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In situ reflectance imaging of organic thin film formation from solution deposition
- 2013
-
In: Solar Energy Materials and Solar Cells. - : Elsevier. - 0927-0248 .- 1879-3398. ; 114, s. 89-98
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Journal article (peer-reviewed)abstract
- In this work we present reflectance imaging as a suitable method for in situ monitoring of the drying process of film formation for organic photovoltaics (OPV) over large areas, as well as for lab-scale spin-coating. The drying wet film is illuminated with a narrow bandwidth LED with the specularly reflected light recorded by a video camera as the film dries and forms the active layer of the OPV cell. The interference fringes generated by the thinning wet film can be used to measure the rate of solvent evaporation and the drying time. Subsequent mapping elucidates variations in drying conditions over the substrate, which lead to variations in morphology formation. The technique is suitable for tracking thickness variations of the dry film, with a sensitivity of 10 nm, by comparing the intensity of the reflected light from the dry film to simulated interference conditions calculated for each thickness. The drying process is furthermore accurately simulated by an optical model considering the changes in refractive index as the amount of solvent decreases with respect to the solid content. This non-invasive in situ method represents an important monitoring tool for future large scale OPV manufacturing where high performing morphologies with uniform thickness have to be formed over very large areas.
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| 18. |
- Bergqvist, Jonas, et al.
(author)
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LED array scanner for inline characterization of thin film photovoltaic modules
- 2016
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In: Solar Energy Materials and Solar Cells. - : Elsevier. - 0927-0248 .- 1879-3398. ; 157:17, s. 1057-1064
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Journal article (peer-reviewed)abstract
- Thin film solar cells, and in particular printed organic solar cells, offer a potential route to a low cost power generation from sunlight. However, manufacturing these solar cells rapidly generates large areas that have to be characterized, preferably in-line for a direct feed back in the production process. Here we introduce the LEDimage, a LED array illumination induced photocurrent method suitable for high speed inline characterization and defect detection of organic solar cell modules. The LEDimage enables simultaneous illumination of all connected subcells without additional bias light. Each LED in the array is amplitude modulated at an individual frequency and the photocurrent response is Fourier transformed to generate a photocurrent map. Furthermore, the LEDimage can be used as a hand scanner for fast device characterization. We expect that LEDimage can be an effective research and industry tool for characterization of large area thin film solar cells.
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| 19. |
- Boström, Tobias, et al.
(author)
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ERDA of Ni-Al2O3/SiO2 solar thermal selective absorbers
- 2008
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In: Solar Energy Materials and Solar Cells. - : Elsevier BV. - 0927-0248 .- 1879-3398. ; 92:10, s. 1177-1182
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Journal article (peer-reviewed)abstract
- Thin film materials for the use in solar thermal absorbers have been investigated using time-of-flight energy elastic recoil detection analysis (ERDA). The ERDA measurements proved to be very efficient in detecting the elemental depth composition of a selective solar absorber. The three-layer absorber is composed of an 80% nickel-20% alumina film at the base, a 40% nickel-60% alumina layer in the middle and finally an AR film of silica or hybrid-silica film at the top. The difference between solution volume percent and actual volume percent could be investigated when studying individual nickel-alumina films with varying ratios coated on glass substrates. The result showed that there was a maximum difference of 3% between the calculated solution volume percent and the actual volume percentages in the solid films. The ERDA measurements also indicate that about 15% of the nickel found in the nickel-alumina composite films is bound in the form of NiO.
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| 20. |
- Boström, Tobias, et al.
(author)
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Optimization of a solution-chemically derived solar absorbing spectrally selective surface
- 2007
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In: Solar Energy Materials and Solar Cells. - : Elsevier BV. - 0927-0248 .- 1879-3398. ; 91:1, s. 38-43
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Journal article (peer-reviewed)abstract
- A previously studied solution chemically derived two layer absorber has been improved by adding a third layer. Simulations done with a thin film program showed that the optimized three layer selective absorber should be composed of an 80% nickel-20% alumina film of 100 nm at the base, a 40% nickel-60% alumina film of 60 nm in the middle and finally a 100% silica film of 85 nm at the top. Experimental results confirmed the computer simulated three layer structure. Prepared absorber consisting of the theoretically found optimized layer structure achieved a solar absorptance, alpha(sol), of 0.97 and a thermal emittance, epsilon(therm), of 0.05.
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| 21. |
- Brogren, M, et al.
(author)
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Optical properties, durability, and system aspects of a new aluminium-polymer-laminated steel reflector for solar concentrators
- 2004
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In: Solar Energy Materials and Solar Cells. - : Elsevier BV. - 0927-0248 .- 1879-3398. ; 82:3, s. 387-412
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Journal article (peer-reviewed)abstract
- A newly developed aluminium-polymer-laminated steel reflector for use in solar concentrators was evaluated with respect to its optical properties, durability, and reflector performance in solar thermal and photovoltaic systems. The optical properties of the reflector material were investigated using spectrophotometer and scatterometry. The durability of the reflector was tested in a climatic test chamber as well as outdoors in Alvkarleby (60.5degreesN, 17.4degreesE), Sweden. Before ageing, the solar weighted total and specular reflectance values were 82% and 77%, respectively, and the reflector scattered light isotropically. After I year's outdoor exposure, the total and specular solar reflectance had decreased by less than 11%. However, after 2000 h in damp heat and 1000 W/m(2) simulated solar radiation, the optical properties had changed significantly: The light scattering was anisotropic and the total and specular solar reflectance values had decreased to 75% and 42%, respectively. The decrease was found to be due to degradation of the protective polyethylene terephthalate (PET) layer, caused by UV radiation and high temperature. The conclusions are that the degradation is climate dependent and that PET is not suitable as a protective coating under extreme conditions, such as those in the climatic test chamber. However, the results from outdoor testing indicate that the material withstands exposure in a normal Swedish climate.
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| 22. |
- Bruder, Ingmar, et al.
(author)
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Efficient organic tandem cell combining a solid state dye-sensitized and a vacuum deposited bulk heterojunction solar cell
- 2009
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In: Solar Energy Materials and Solar Cells. - : Elsevier BV. - 0927-0248 .- 1879-3398. ; 93:10, s. 1896-1899
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Journal article (peer-reviewed)abstract
- In this letter, we report on an efficient organic tandem solar cell combining a solid state dye-sensitized with a ZnPc/C60-based, vacuum deposited bulk heterojunction solar cell. Due to an effective serial connection of both subcells and to the complementary absorption of the dyes used, a power conversion efficiency of ηp=(6.0±0.1)% was achieved under simulated AM 1.5 illumination. The device parameters are , and FF=(54±1)%.
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| 23. |
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| 24. |
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| 25. |
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