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  • 1.
    Chen, Zhi-Hui
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Hellström, Staffan
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Yu, Zhong-Yuan
    Fu, Ying
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Comb-shaped photonic crystal structure for efficient broadband light diffraction and funnelling in solar cells2012In: Solar Energy Materials and Solar Cells, ISSN 0927-0248, E-ISSN 1879-3398, Vol. 99, p. 316-320Article in journal (Refereed)
    Abstract [en]

    We present a comb-shaped photonic-crystal (PhC) rods-lattice structure of broadband light diffraction and funnelling for solar cell applications. It is shown that the photonic band of this PhC structure is very dispersive over a broad bandwidth so that light will be efficiently diffracted in the wavelength region of solar radiation. The PhC structure also creates resonance modes leading to further diffraction and funnelling of light so that the light propagates in many pathways in the whole PhC lattice region, which will greatly facilitate light-matter interaction when light-absorbing elements are embedded in the PhC structure. The proposed structure is also valid for photodetection applications.

  • 2. Crovetto, Andrea
    et al.
    Chen, Rongzhen
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Ettlinger, Rebecca Bolt
    Cazzaniga, Andrea Carlo
    Schou, Jorgen
    Persson, Clas
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Hansen, Ole
    Dielectric function and double absorption onset of monoclinic Cu2SnS3: origin of experimental features explained by first-principles calculations2016In: Solar Energy Materials and Solar Cells, ISSN 0927-0248, E-ISSN 1879-3398, Vol. 154, p. 121-129Article in journal (Refereed)
    Abstract [en]

    In this work, we determine experimentally the dielectric function of monoclinic Cu2SnS3 (CTS) by spectroscopic ellipsometry from 0.7 to 5.9 eV. An experimental approach is proposed to overcome the challenges of extracting the dielectric function of Cu2SnS3 when grown on a glass/Mo substrate, as relevant for photovoltaic applications. The ellipsometry measurement reveals a double absorption onset at 0.91 eV and 0.99 eV. Importantly, we demonstrate that calculation within the density functional theory (DFT) confirms this double onset only when a very dense k-mesh is used to reveal fine details in the electronic structure, and this can explain why it has not been reported in earlier calculated spectra. We can now show that the double onset originates from optical transitions at the Gamma-point from three energetically close-lying valence bands to a single conduction band. Thus, structural imperfection, like secondary phases, is not needed to explain such an absorption spectrum. Finally, we show that the absorption coefficient of CTS is particularly large in the near-band gap spectral region when compared to similar photovoltaic materials. (C) 2016 Elsevier B.V. All rights reserved.

  • 3. Fabregat-Santiago, F.
    et al.
    Bisquert, J.
    Garcia-Belmonte, G.
    Boschloo, Gerrit
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Physical Chemistry.
    Hagfeldt, Anders
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Influence of electrolyte in transport and recombination in dye-sensitized solar cells studied by impedance spectroscopy2005In: Solar Energy Materials and Solar Cells, ISSN 0927-0248, E-ISSN 1879-3398, Vol. 87, no 04-jan, p. 117-131Article in journal (Refereed)
    Abstract [en]

    The main features of the characteristic impedance spectra of dye-sensitized solar cells are described in a wide range of potential conditions: from open to short circuit. An equivalent circuit model has been proposed to describe the parameters of electron transport, recombination, accumulation and other interfacial effects separately. These parameters were determined in the presence of three different electrolytes, both in the dark and under illumination. Shift in the conduction band edge due to the electrolyte composition was monitored in terms of the changes in transport resistance and charge accumulation in TiO2. The interpretation of the current-potential curve characteristics, fill factor, open-circuit photopotential and efficiency in the different conditions, was correlated with this shift and the features of the recombination resistance.

  • 4.
    Fischer, Andreas
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Inorganic Chemistry.
    Pettersson, Henrik
    Hagfeldt, Anders
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Boschloo, Gerrit
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Physical Chemistry.
    Kloo, Lars A.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Inorganic Chemistry.
    Gorlov, Mikhail
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Inorganic Chemistry.
    Crystal formation involving 1-methylbenzimidazole in iodide/triiodide electrolytes for dye-sensitized solar cells2007In: Solar Energy Materials and Solar Cells, ISSN 0927-0248, E-ISSN 1879-3398, Vol. 91, no 12, p. 1062-1065Article in journal (Refereed)
    Abstract [en]

    Nitrogen heterocyclic compounds, such as N-methylbenzimidazole (MBI), are commonly used as additives to electrolytes for dye-sensitized solar cells (DSCs), but the chemical transformation of additives in electrolyte solutions remains poorly understood. Solid crystalline compound (MBI)(6)(MBI-H+)(2)(I-)(I-3(-)) (1) was isolated from different electrolytes for DSCs containing MBI as additive. The crystal structure of I was determined by single-crystal X-ray diffraction. In the crystal structure, 1 contains neutral and protonated MBI fragments; iodide and triiodide anions form infinite chains along the crystallographic a-axis. The role of the solvent and additives in the crystallization process in electrolytes is discussed.

  • 5.
    Fredin, Kristofer
    et al.
    Department of Physical Chemistry, Uppsala University.
    Nissfolk, Jarl
    Department of Physical Chemistry, Uppsala University.
    Hagfeldt, Anders
    Department of Physical Chemistry, Uppsala University.
    Brownian dynamics simulations of electrons and ions in mesoporous films2005In: Solar Energy Materials and Solar Cells, ISSN 0927-0248, E-ISSN 1879-3398, Vol. 86, no 2, p. 283-297Article in journal (Refereed)
    Abstract [en]

    This paper presents a simulation model to study charge transport processes in mesoporous films for dye-sensitized solar cells. By simulating electron and ion transport by Brownian dynamics in these films, we achieve a direct relation between the grain connectivity and the effective diffusion coefficients. By comparing the macroscopic properties of a simple cubic and a diamond structured unit cell, we conclude that the latter better resembles the properties of the mesoporous oxide films in comparison with experimental results. The model has been used to optimize the size of the contact area between the interconnected particles in the mesoporous film with respect to the photocurrent.

  • 6.
    Fredin, Kristofer
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Physical Chemistry.
    Rühle, S.
    Condensed Matter and Interfaces, Debye Institute, Utrecht University.
    Grasso, C.
    Electronics and Information Systems (ELIS), Gent.
    Hagfeldt, Anders
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Physical Chemistry.
    Studies of coupled charge transport in dye-sensitized solar cells using a numerical simulation tool2006In: Solar Energy Materials and Solar Cells, ISSN 0927-0248, E-ISSN 1879-3398, Vol. 90, no 13, p. 1915-1927Article in journal (Refereed)
    Abstract [en]

    In this paper, we present a simulation platform designed to study coupled charge transport in dye-sensitized solar cell (DSC) devices. The platform, SLICE, is used to study the influence of ions in the electrolyte on electron transport in the nanoporous medium. The simulations indicate that both cationic and anionic properties should be considered when modelling DSCs and similar systems. Additionally, it was found that the effective permittivity coefficient, epsilon, has no influence on the electron transport when the ionic concentration is sufficiently high due to the strong coupling between the respective charged species.

  • 7.
    Gunasekara, Samman Nimali
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Chiu, Justin NingWei
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Hedström, Peter
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    The Experimental Phase Diagram Study of the Binary Polyols System Erythritol-Xylitol2017In: Solar Energy Materials and Solar Cells, ISSN 0927-0248, E-ISSN 1879-3398, Vol. 174, p. 248-262Article in journal (Refereed)
    Abstract [en]

    A comprehensive phase diagram for the binary polyols system erythritol-xylitol has been mapped with a transparent characterization approach. Here, the phase equilibrium of the system has been studied experimentally using a combination of methods: Temperature-history (T-history), X-Ray Diffraction (XRD), and Field-Emission Scanning Electron Microscopy (FESEM), and linked to Tammann plots. Existing literature has previously shown the system to be a non-isomorphous type forming a simple eutectic, by combining experimental data with theoretical modelling. The present investigation shows that the system’s phase diagram is a partially isomorphous type forming a eutectic, but not a non-isomorphous type forming a simple eutectic. Here, the eutectic was found within 25-30 mol% erythritol and at 77 °C, which differs from the previous studies identifying the eutectic respectively at 25 or 36 mol% erythritol and at 82 °C. The reasons for the differences are hard to deduce since the research approach is not presented as fully transparent from the past studies. In the present study, only the temperature-composition plot of the first melting (of the two components in a physical mix, but not of a single blend) indicated the shape of a simple eutectic in a non-isomorphous system. The cycles after the first melting in contrast started from the real blend, and displayed eutectic and solid-solid phase changes in T-history. These were verified as forming solid solutions with XRD and FESEM. This eutectic melts at a temperature suitable for low-temperature solar heating, but displayed glass transition, supercooling, and thermally activated degradation, thus affecting its practical aspects as a PCM.

  • 8. Li, Chaoyan
    et al.
    Yang, Xichuan
    Chen, Ruikui
    Pan, Jingxi
    Tian, Haining
    Zhu, Hongjun
    Wang, Xiuna
    Hagfeldt, Anders
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Anthraquinone dyes as photosensitizers for dye-sensitized solar cells2007In: Solar Energy Materials and Solar Cells, ISSN 0927-0248, E-ISSN 1879-3398, Vol. 91, no 19, p. 1863-1871Article in journal (Refereed)
    Abstract [en]

    Three anthraquitione dyes with carboxylic acid as anchoring group are designed and synthesized as sensitizers for dye-sensitized solar cells (DSSCs). Preliminary photophysical and photoelectrochemical measurements show that these anthraquinone dyes have very low performance on DSSC applications, although they have broad and intense absorption spectra in the visible region (up to 800nm). Transient absorption kinetics, fluorescence lifetime measurements and density functional theory (DFT) calculations are conducted to investigate the cause of such low DSSC performance for these dyes. The results show that the strong electron -withdrawing character of the two carbonyl groups on anthraquinone framework may lie behind the low performance by suppressing the efficient electron injection from the dye to the conduction band of TiO2.

  • 9. Mahrov, B.
    et al.
    Hagfeldt, Anders
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Lenzmann, F.
    Boschloo, Gerrit
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Physical Chemistry.
    Comparison of charge accumulation and transport in nanostructured dye-sensitized solar cells with electrolyte or CuSCN as hole conductor2005In: Solar Energy Materials and Solar Cells, ISSN 0927-0248, E-ISSN 1879-3398, Vol. 88, no 4, p. 351-362Article in journal (Refereed)
    Abstract [en]

    The charge transport properties of the dye-sensitized solar cells consisting of Ru(dcbpyH(2))(2)(NCS)(2)-sensitized nanostructured TiO2 with either redox electrolyte or CuSCN as hole conductor have been compared. The electron transport time and the electron charge in the TiO2 varies in a similar way with the incident light intensity for both hole conductors: electron transport becomes faster and electron accumulation increases with increasing light intensity. Electron transport in the CuSCN-based cells is significantly faster than in electrolyte cells under conditions where the accumulated charge is equal. An ultra-thin aluminum oxide layer on the nanocrystalline titanium oxide has a beneficial effect as it reduces the recombination and increases the open-circuit potential.

  • 10. Maitani, Masato M.
    et al.
    Tsukushi, Yohei
    Hansen, Niklas D. J.
    KTH, School of Information and Communication Technology (ICT). Tokyo Inst Technol, Japan.
    Sato, Yuka
    Mochizuki, Dai
    Suzuki, Eiichi
    Wada, Yuji
    Low-temperature annealing of mesoscopic TiO2 films by interfacial microwave heating applied to efficiency improvement of dye-sensitized solar cells2016In: Solar Energy Materials and Solar Cells, ISSN 0927-0248, E-ISSN 1879-3398, Vol. 147, p. 198-202Article in journal (Refereed)
    Abstract [en]

    Novel interfacial microwave heating of a layered structure has been applied to the process of low temperature annealing of titania mesoporous films for dye-sensitized solar cells. Interfacial microwave annealing dramatically enhances the cell performances as compared with conventional heating in an electric oven. The improvement of cell performance is attributed to the electron transport properties in the titania films annealed by MW resulting in longer diffusion length as compared with conventional heating.

  • 11.
    Palmgren, Pål
    et al.
    KTH, School of Information and Communication Technology (ICT), Material Physics.
    Priya, Baskar Rao
    KTH, School of Information and Communication Technology (ICT), Material Physics.
    Niraj, N. Pio Peter
    KTH, School of Information and Communication Technology (ICT), Material Physics.
    Göthelid, Mats
    KTH, School of Information and Communication Technology (ICT), Material Physics.
    Bonding of metal-free phthalocyanine to TiO2(110) single crystal2006In: Solar Energy Materials and Solar Cells, ISSN 0927-0248, E-ISSN 1879-3398, Vol. 90, no 20, p. 3602-3613Article in journal (Refereed)
    Abstract [en]

    The metal-free phthalocyanine interface formation on rutile TiO2(110) is investigated using scanning tunneling microscopy and photoelectron spectroscopy. The molecules are adsorbed flat on the surface, centered on the substrate oxygen rows. High-resolution core-level C1s spectroscopy indicates a strong difference between the second layer and the first monolayer bonding to the surface. The C1s core-level from the second layer has a bulk-like line shape whereas the first layer shows a strongly modified line profile. Upon thermal treatment, changes in the N1s core level line profile points to dehydrogenation of the center of the molecule.

  • 12.
    Paulsson, Heléne
    et al.
    KTH, Superseded Departments, Chemistry.
    Berggrund, Malin
    KTH, Superseded Departments, Chemistry.
    Svantesson, Eva
    Hagfeldt, Anders
    Kloo, Lars A.
    KTH, Superseded Departments, Chemistry.
    Molten and Solid Metal-Iodide-Doped Trialkylsulphonium Iodides and Polyiodides as Electrolytes in Dye-Sensitized Nanocrystalline Solar Cells2004In: Solar Energy Materials and Solar Cells, ISSN 0927-0248, E-ISSN 1879-3398, Vol. 82, no 3, p. 345-360Article in journal (Refereed)
    Abstract [en]

    The conductivity and solar cell performance of metal-iodide-doped trialkylsulphonium iodides and polyiodides have been investigated as electrolytes in dye-sensitized nanocrystalline solar cells (DNSCs). Nine different metal-iodide-containing (R2R′S)I with additional iodine provided overall solar-to-electric energy conversion efficiencies of over 2%, while used as electrolytes in DNSCs in simulated AM 1.5 solar light at the light intensity of 100Wm-2. The highest overall conversion efficiency, 3.1%, was achieved by using the electrolyte (Bu2MeS)I: AgI:I2 in the proportions (1:0.03:0.05). The effects from 4-tert-butylpyridine treatment of the electrodes were studied. The effects of metal-iodide doping were also investigated with respect to speciation in the electrolytes and potential influence on electrochemical conductivity.

  • 13. Reddy, Vasudeva Reddy Minnam
    et al.
    Lindwall, Greta
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering. Pennsylvania State University, United States .
    Pejjai, Babu
    Gedi, Sreedevi
    Kotte, Tulasi Ramakrishna Reddy
    Sugiyama, Mutsumi
    Liu, Zi-Kui
    Park, Chinho
    alpha-SnSe thin film solar cells produced by selenization of magnetron sputtered tin precursors2018In: Solar Energy Materials and Solar Cells, ISSN 0927-0248, E-ISSN 1879-3398, Vol. 176, p. 251-258Article in journal (Refereed)
    Abstract [en]

    The temperature-pressure-composition phase diagrams of Sn-Se system were calculated using the CALPHAD (CALculation of PHase Diagram) models. The phase diagrams showed the formation of alpha-SnSe phase at selenium-rich side with pressures lower than atmospheric pressure and in the temperature range of 300-500 degrees C. As a first step, the effect of Sn/Se ratio on the phase formation was studied experimentally by selenization of tin metal precursor films using effusion cell evaporation. The Sn/Se ratio was varied by changing the selenium weight in the range of 0.5-1.5 g. The physical properties of the films were studied with suitable characterization techniques and the obtained results showed the formation of single phase alpha-SnSe at 1.0 g of selenium. Further, alpha-SnSe/CdS interface was studied by photoelectron yield spectroscopy (PYS), which showed a 'type-I' band alignment with a valence-band offset (Delta E-v) of 1.3 eV and a conduction-band offset (Delta E-c) of 0.2 eV. Finally, alpha-SnSe solar cells with a device structure of soda-lime glass (SLG)/Mo/alpha-SnSe/CdS/i-ZnO/Al:ZnO/Ni/Ag were fabricated and a power conversation efficiency of 1.42% was achieved at 1.0 g of selenium.

  • 14. Suvanam, S. S.
    et al.
    Larsen, J.
    Ross, N.
    Kosyak, V.
    Hallén, Anders
    KTH, School of Information and Communication Technology (ICT).
    Björkman, C. P.
    Extreme radiation hard thin film CZTSSe solar cell2018In: Solar Energy Materials and Solar Cells, ISSN 0927-0248, E-ISSN 1879-3398, Vol. 185, p. 16-20Article in journal (Refereed)
    Abstract [en]

    In this work, we have demonstrated the extreme radiation hardness of thin film CZTSSe solar cells. Thin film solar cells with CZTSSe, CZTS and CIGS absorber layers were irradiated with 3 MeV protons. No degradation in device parameters was observed until a displacement damage dose of 2 × 1010 MeV/g for CZTS and CZTSSe. CIGS solar cells degraded by 13% at the same dose. For the highest proton dose both the CZTSSe and CZTS degraded by 16% while CIGS suffered from 34% degradation in efficiency. The degradation in efficiency maybe attributed to the reduction in the minority carrier lifetime due to radiation induced lattice defects. Comparisons with previously available literature show that our CZTS technology has superior radiation hardness by about two orders of magnitude compared to existing state of the art Si and GaAs technology.

  • 15. Syväjärvi, M.
    et al.
    Ma, Q.
    Jokubavicius, V.
    Galeckas, A.
    Sun, J.
    Liu, X.
    Jansson, M.
    Wellmann, P.
    Linnarsson, Margareta
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Runde, P.
    Johansen, B. A.
    Thøgersen, A.
    Diplas, S.
    Carvalho, P. A.
    Løvvik, O. M.
    Wright, D. N.
    Azarov, A. Y.
    Svensson, B. G.
    Cubic silicon carbide as a potential photovoltaic material2016In: Solar Energy Materials and Solar Cells, ISSN 0927-0248, E-ISSN 1879-3398, Vol. 145, p. 104-108Article in journal (Refereed)
    Abstract [en]

    In this work we present a significant advancement in cubic silicon carbide (3C-SiC) growth in terms of crystal quality and domain size, and indicate its potential use in photovoltaics. To date, the use of 3C-SiC for photovoltaics has not been considered due to the band gap of 2.3 eV being too large for conventional solar cells. Doping of 3C-SiC with boron introduces an energy level of 0.7 eV above the valence band. Such energy level may form an intermediate band (IB) in the band gap. This IB concept has been presented in the literature to act as an energy ladder that allows absorption of sub-bandgap photons to generate extra electron-hole pairs and increase the efficiency of a solar cell. The main challenge with this concept is to find a materials system that could realize such efficient photovoltaic behavior. The 3C-SiC bandgap and boron energy level fits nicely into the concept, but has not been explored for an IB behavior. For a long time crystalline 3C-SiC has been challenging to grow due to its metastable nature. The material mainly consists of a large number of small domains if the 3C polytype is maintained. In our work a crystal growth process was realized by a new approach that is a combination of initial nucleation and step-flow growth. In the process, the domains that form initially extend laterally to make larger 3C-SiC domains, thus leading to a pronounced improvement in crystalline quality of 3C-SiC. In order to explore the feasibility of IB in 3C-SiC using boron, we have explored two routes of introducing boron impurities; ion implantation on un-doped samples and epitaxial growth on un-doped samples using pre-doped source material. The results show that 3C-SiC doped with boron is an optically active material, and thus is interesting to be further studied for IB behavior. For the ion implanted samples the crystal quality was maintained even after high implantation doses and subsequent annealing. The same was true for the samples grown with pre-doped source material, even with a high concentration of boron impurities. We present optical emission and absorption properties of as-grown and boron implanted 3C-SiC. The low-temperature photoluminescence spectra indicate the formation of optically active deep boron centers, which may be utilized for achieving an IB behavior at sufficiently high dopant concentrations. We also discuss the potential of boron doped 3C-SiC base material in a broader range of applications, such as in photovoltaics, biomarkers and hydrogen generation by splitting water.

  • 16.
    Wang, Baoyuan
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology. Hubei University, China.
    Cai, Yixiao
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology. Uppsala University, Sweden.
    Dong, Wenjing
    Xia, Chen
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology. Hubei University, China.
    Zhang, Wei
    Liu, Yanyan
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Afzal, Muhammad
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Wang, Hao
    Zhu, Bin
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology. Hubei University, China.
    Photovoltaic properties of LixCo3-xO4/TiO2 heterojunction solar cells with high open-circuit voltage2016In: Solar Energy Materials and Solar Cells, ISSN 0927-0248, E-ISSN 1879-3398, Vol. 157, p. 126-133Article in journal (Refereed)
    Abstract [en]

    All-oxide solar cells are presently attracting extensive research interest due to their excellent stability, low-cost and non-toxicity. However, the band gap of metal oxides is lack of effective optimization and results in poor photovoltaic performance, thus hindering their practical applications. In this work, Co3O4 was investigated for application as a photo-absorber in all-oxide solar cells, and its band gap was optimized by introducing Li dopant into the spinel structure. LixCo3-xO4 nanoparticles, prepared via the hydrothermal method, were homogenously coated onto TiO2 mesoporous films, which were then used to fabricate planar heterojunction TiO2/LixCo3-xO4 solar cells (SCs). The effects of Li-doping on the heterojunction solar cell performance were further investigated. The findings revealed that the incorporation of Li ions into Co3O4 led to a significant enhancement in short-circuit current density (J(sc)). Remarkably, a high open-circuit voltage (V-oc) of 0.70 V was also achieved. Besides, reasons for the enhanced cell performance are the narrower band gap, reduced photogenerated carrier recombination and the more favorable energy band structure as compared with SCs assembled from pure Co3O4.

  • 17.
    Wang, Wujun
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Effect of cavity surface material on the concentrated solar flux distribution for an impinging receiver2017In: Solar Energy Materials and Solar Cells, ISSN 0927-0248, E-ISSN 1879-3398, Vol. 161, p. 177-182Article in journal (Refereed)
    Abstract [en]

    In this paper, the effects of cavity surface materials on the radiative flux distribution of solar cavity receivers have been studied with the help of a ray-tracing methodology. Three metallic substrate materials (Inconel 600, austenitic stainless steel 253 MA and Kanthal APM) and two coating materials (Pyromark® 2500 coating and YSZ TBC coating) were selected as the candidate cavity surface materials. The results show that the flux distribution and the total optical efficiency are much more sensitive to the absorptivity on the cylindrical surface than on the bottom. By using high absorptivity coating on the cylindrical surface and low absorptivity coating on the bottom, the radiative flux on the bottom can be controlled at a low level, and it can help to reduce the cavity length for an impinging receiver with jets on the cylindrical surface. Furthermore, the radiative flux distribution on the cylindrical surface can also be tailored to meet various design requirements by applying different coating designs on the cylindrical surface.

  • 18.
    Zhao, Ruikai
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering. Tianjin Univ, Minist Educ, Key Lab Efficient Utilizat Low & Medium Grade Ene, Tianjin 300350, Peoples R China.
    Zhao, Li
    Tianjin Univ, Minist Educ, Key Lab Efficient Utilizat Low & Medium Grade Ene, Tianjin 300350, Peoples R China..
    Wang, Shengping
    Tianjin Univ, Sch Chem Engn & Technol, Key Lab Green Chem Technol, Tianjin 300072, Peoples R China..
    Deng, Shuai
    Tianjin Univ, Minist Educ, Key Lab Efficient Utilizat Low & Medium Grade Ene, Tianjin 300350, Peoples R China..
    Li, Hailong
    Malardalen Univ, Sch Business Soc & Engn, SE-72123 Vasteras, Sweden..
    Yu, Zhixin
    Univ Stavanger, Dept Petr Engn, N-4036 Stavanger, Norway..
    Solar-assisted pressure-temperature swing adsorption for CO2 capture: Effect of adsorbent materials2018In: Solar Energy Materials and Solar Cells, ISSN 0927-0248, E-ISSN 1879-3398, Vol. 185, p. 494-504Article in journal (Refereed)
    Abstract [en]

    Because of the ability to utilize the low-grade solar thermal energy for regeneration, a CO2 capture system characterized by solar-assisted pressure temperature swing adsorption (SOL-PTSA) is studied on the effects of adsorbent materials. A detailed cycle description is firstly presented within the diagram of adsorption isotherm for the energy-efficiency analysis. Typical adsorbent materials, including zeolites and chemical adsorbent, are assessed in terms of sensible heat and latent heat, etc. Then, the energy consumption and the second-law efficiency, which can be considered as lumped indicators from such material parameters, are chosen as performance indicators as well. The influence of separation temperature, desorption temperature, CO2 concentration and CO2 adsorption pressure on system performance are finally obtained. For the chosen three adsorbent materials, the energy consumption of SOL-PTSA system is at the range of 25.96-87.76 kJ/mol, and the corresponding second law efficiencies are at the range of 9.18-26.89%. The effect of adsorbent materials on the energy-efficiency of SOL-PTSA system mainly depends on specific heat, CO2 working capacity and cycle design. In addition, the integration options of solar energy into PTSA technology are also discussed from the standpoint of the utilization of solar grade heat due to two energy loads required for PTSA's operation.

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