About
55
Publications
14,941
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
743
Citations
Citations since 2017
Publications
Publications (55)
Les énergies renouvelables font partie intégrante de la stratégie énergétique de la plupart des pays. Ce contexte engage à considérer avec attention toutes les solutions qui peuvent contribuer à l’émergence d’un monde décarboné. Parmi ces solutions, le solaire occupe une position de choix avec ses modes de conversion photovoltaïque et thermique, do...
Herein, we introduce a bottom-up material design approach of optically selective SiC-based nanocomposite objects. Precursors have been firstly synthesized by reaction of allylhydridopolycarbosilane with titanium and boron complexes before a pyrolysis at 1000 °C in flowing argon to deliver single-phase amorphous Si–Ti–C–N(B,H) ceramics. The later wa...
This chapter on the materials for concentrated solar power systems focuses on optical components. It describes the general optics elements. The chapter provides details on the three types of optical surfaces that are used in solar fields: reflective, transparent and absorbing surfaces. It defines the performance indicators associated with the consi...
We report a solar selective coating of W/WAlSiN/SiON/SiO2 fabricated using a Four-Cathode Reactive Unbalanced Direct Current (DC) magnetron sputtering system with high thermal stability, good durability and resistance to outdoor testing conditions. The coating also exhibits superior mechanical properties (Hardness ∼12 GPa). In addition, thermal sho...
In concentrated solar power (CSP), selective solar absorber coatings increase absorbed solar flux (high solar absorptance AS) while reducing radiative losses (low thermal emittance EBB). Coating developers usually maximize the selective ratio As/EBB (highest As, lowest EBB). The solar-to-heat conversion (heliothermal) efficiency Rh of a solar absor...
Silver is a strategic material for renewable energy. Among other applications related to PV, it is used as reflective layer in solar mirrors for concentrated solar power (CSP), thanks to its high reflectance in the whole solar range. CSP plants require large mirror areas, typically in the 0.1 to 1 km². However the estimated reserves of silver do no...
Spectrally selective W/WAlSiN/SiON/SiO2 solar absorber coatings were sputter-deposited on stainless steel and silicon substrates. The optimized as-deposited sample exhibits a high solar absorptance of 0.955 and a low thermal emissivity of 0.10 at 82 °C. The coating exhibits a very low reflectance of 1.2% in the wavelength range of 0.5–1.5 μm in the...
In concentrating solar power (CSP) technologies, the absorber material should be spectrally selective under severe operating conditions, i.e., ~1000 °C under air atmosphere. SiC–TiC nanocomposites could be good candidates for this application due to their spectral selectivity at room temperature; however, their behaviour under CSP operating conditi...
Materials for solar receivers in concentrated solar power plants are subjected to harsh working conditions including high temperatures, thermal shocks, and cycling, which cause high thermal and mechanical stresses in the materials. Ceramics are, therefore, excellent candidates as solar receiver materials for their high thermal, chemical, and mechan...
High thermal stability and resistance to oxidation at atmospheric conditions need to be critically proven to ensure a long lifetime of the receiver of concentrated solar power plants. In the present work, the titanium aluminum nitride tandem absorbers are showing one of the most promising selective coating solutions for solar receivers operating at...
Spectral emissivity is considered as one of the most critical thermophysical properties influencing photothermal conversion efficiency of solar selective absorbers. In addition, long term stability at high temperature and thermal shock resistance are the performance-limiting properties of spectrally selective absorbers. In this context, the present...
In this study, the potential of SiC-TiC nano-composites as solar absorbers has been studied. For solar thermal applications, materials with high solar absorptance and low emittance are ideally sought for (spectral selectivity). A semi-molecular sol-gel synthesis route leading to nanometric homogenous composites was described. The resulting SiC-TiC...
CSP (Concentrated Solar Power) plants technologies use the concentration of solar energy on a receiver to produce heat and then electricity by a thermodynamical process. A solar absorber material is used to convert the energy carried by light into heat. This type of material works at high temperatures (up to 1000 °C) under a highly concentrated sol...
Cr2O3/Cr/Cr2O3 multilayered selective solar absorber coating was deposited onto stainless steel substrates using electron beam vacuum evaporation at room temperature. The optical constants of the individual layers were obtained from reflectance measurements fitted by CODE software using the suitable dielectric function model, and showed that both C...
Based on an optimized TiAlN multilayer structure achieving high absorption and low thermal emission at temperatures above 500°C for CSP receivers, the authors demonstrate that - sub-wavelength period gratings associated with the multilayer can further increase the absorption and thus the efficiency of the CSP system. The C-method (Chandezon Method)...
In many areas which call for solar radiation harvesting, from buildings to solar power plants, all manners of windows and protective glass envelopes are required. A high transmission of solar light through glass is therefore mandatory, mostly in the visible range for lighting purposes and also in the near infrared range for power generation. For th...
Desert dune sand is considered as a potential sensible heat thermal energy storage (TES) material. Several samples are collected from different locations of the desert in the United Arab Emirates (UAE), and relevant thermophysical and mechanical properties are measured. In addition, the optical properties of desert sand are investigated to evaluate...
A spectrally selective TiAlC/TiAlCN/TiAlSiCN/TiAlSiCO/TiAlSiO coating was deposited on stainless steel substrate by unbalanced magnetron sputtering system. Each individual layer of the tandem absorber was optimized by varying the reactive gas flow rates (C2H2, N2 and O2) and target power densities (Ti, Al and Si). The optimized tandem absorber show...
Solar selective absorber coatings, consisting in a TiAlNx / TiAlNy tandem absorber with low (metallic-like) and high (semiconductor-like) nitrogen content, and an Al2O3 antireflective coating, were deposited on stainless steel. A full optical characterization was carried out on these coatings. Reflectance spectra were measured by spectrophotometry...
TiAlC, TiAlCN, TiAlSiCN, TiAlSiCO, and TiAlSiO layers of thicknesses ~2.2 μm, 755, 491, 393, and 431 nm, respectively, were deposited on stainless steel, silicon, and glass substrates to study their refractive indices and extinction coefficients using the phase-modulated spectroscopic ellipsometry in the wavelength range of 300–1200 nm. Absorption...
This chapter helps to establish a state of the art on selective surfaces for solar thermal energy conversion. It reviews the different approaches, from tandem to double cermet and multilayer absorber stacks, as well as the corresponding deposition processes and optimization strategies, including aging behavior and durability. The chapter focuses on...
This study presents a rigorous modeling approach for 1D microstructured absorbing multi-layers for Concentrated Solar Power (CSP) receivers, taking into account both the absorption of the incident solar energy as well as the emissivity for the desired receiver temperature. Based on an optimized multilayer structure achieving high absorption, the au...
CSP (Concentrated Solar Power) parabolic-trough and Linear Fresnel Reflector absorbers, convert sunlight into heat for producing electrical energy, reaching temperatures of about 250-450°C. At this working temperature thermal losses are mainly radiative. Thus, the absorber must be coated with spectrally selective films, with good solar absorbance p...
Desert sand from the United Arab Emirates (UAE) is considered as a possible sensible heat, thermal energy storage (TES) material. Its thermal stability,
specific heat capacity and tendency to agglomerate are studied at high temperatures. The analyses show that it is possible to use desert sand as a TES material up to 800-1000 °C. Above 800 °C, weak...
The paper presents preliminary results of a partnership project between academic research groups and industrial partners. The LFR500 project aims at developing a prototype of Linear Fresnel Reflector (LFR) solar power plants able to work above 500°C providing Direct Steam Generation (DSG) under 90 bars. LFR plants usually operate at 300°C, but at 5...
The paper demonstrates a rigorous modeling approach for 1D microstructured absorbing multi-layers for the receivers of CSP (Concentrated Solar Power), taking into account both absorption of the incident solar energy and the emissivity while considering receivers temperature. From an optimized multilayers structure achieving high absorption, the aut...
Undoped and nitrogen doped TiO2
thin films were deposited by atomic layer deposition on planar substrates. Deposition on 3D-architecture substrates made of metallic foams was also investigated to propose architectured photovoltaic stack fabrication. All the films were deposited at 265 °C and nitrogen incorporation was achieved by using titanium iso...
During the past decade multi-dipolar plasmas have been employed for various purposes such as surface treatments in biomedicine, physical and chemical vapour deposition for hydrogen storage, and applications in mechanical engineering. On the other hand, due to the design and operational mode of these plasma sources (i.e., strong permanent magnets fo...
SiCH thin films grown from Ar/tetramethylsilane plasmas (PECVD) were evaluated as absorber layers in selective coatings for high-temperature solar receivers. SiCH coatings are used in thermomechanical applications because of their good thermal stability. A SiCH film with an absorption index k(430 nm)=0.11 was taken as a reference for optical simula...
Nitrogen-doped TiO2 thin films were deposited by atomic layer deposition on glass substrates with various nitrogen concentrations for potential use in photovoltaic applications as a transparent p-type layer. Nitrogen doping was achieved by combining the use of titanium isopropoxide, N2O and NH3 as precursors. All the films were deposited at 265 °C....
SiCNH thin coatings synthesized by Plasma Enhanced Chemical Vapor Deposition (PECVD) are considered as high temperature ceramic materials for solar selective multilayer absorbers. As indicated by ellipsometry and spectrophotometry measurements, their optical characteristics make them suitable as solar absorbing and antireflective coatings in multil...
As an alternative to laser induced fluorescence (TALIF) for H atom density measurement, a method called "refine actinometry" using a combination of optical emission spectroscopy and Langmuir probe measurements is evaluated. This evaluation has been performed both experimentally and theoretically. Experiments have provided variations of H atom densi...
In parallel to the ITER tokamak construction is raising the question of the next step toward a real Fusion power plant (called DEMO reactor), which should be a full ignition and high power fusion machine. It is highly desirable for new reactor to find alternatives to the use of caesium (Cs) due to several important drawbacks like a very high Cs con...
In the present global environmental context, it becomes more and more critical to find efficient solutions to lower our energy consumption on one hand, and to produce energy from clean renewable sources on the other hand. Consequently, research efforts on materials for energy applications are intensifying.
The present work aims at developing optoel...
In conventional sterilization methods (steam, ozone, gaseous chemicals), after their proper cleaning, medical devices are wrapped/enclosed in adequate packaging materials, then closed/sealed before initiating the sterilization process: these packaging materials thus need to be porous. Gaseous plasma sterilization being still under development, eval...
Amorphous hydrogenated silicon carbide (a-SiC:H) coatings are promising candidates for tribological applications in the mechanical and aeronautical industries. Alternately high values of hardness H (15 < H < 32 GPa) and elastic modulus E contribute to their good wear resistance as well as to a low friction coefficient. The latter has been found to...
Titanium alloys are commonly used to lighten aeronautical structures. Unfortunately, their poor tribological properties need to confer onto the surface both high mechanical resistance under load and low friction/low wear against other metals. Based on amorphous silicon carbide (a-SiC:H), periodic multi-nano-coatings have been found to be candidates...
Amorphous hydrogenated silicon carbide films were grown from capacitively coupled low frequency argon–tetramethylsilane plasmas. Mass spectrometry, optical emission spectroscopy and electrostatic probe were used to identify electron properties and chemical species under various deposition conditions. Film microstructure and mechanical properties we...
a-SiC:H films prepared by plasma-assisted chemical vapor deposition (PACVD) are good candidates for mechanical applications as they present high hardness (H) and Young's modulus (E) as well as good resistance to wear and friction. In this work, a-SiC:H coatings are grown from argon/tetramethylsilane [TMS: Si(CH3)4] gas mixtures in a low frequency P...
A capacitively coupled low frequency PACVD device (ν = 50 kHz, DC bias: |Vdc| = 0 to 400 V) is used to deposit hard amorphous silicon carbide films (a-SiC:H), from the decomposition of precursor tetramethylsilane (TMS) diluted in argon. Such a deposition process induces an ion bombardment of the growing films: energetic ions can sputter atoms from...
Hard coatings have received considerable attention for many mechanical applications, such as aeronautics, space and high precision mechanics. Material properties, like high hardness, low friction and low wear versus metals, are required for this purpose. Diamondlike carbon films (a-C:H, DLCs) fulfill these requirements. Nevertheless, they are limit...
Hard silicon carbide based films (a-SiC:H) are obtained in a capacitively coupled low frequency PACVD device from the decomposition of tetramethylsilane (TMS) diluted in argon (ν = 50 KHz, DC bias: ∣Vdc∣ = 0–400 V). To get a better understanding of the effect of ion bombardment occurring during growth, optical emission spectroscopy was performed ne...
RESUME: Les dépôts a-SiC:H montrent un potentiel important en application mécanique (automobile, aéronautique). Leurs forts module d'élasticité (150 < E < 230 GPa) et dureté (15 < H < 32 GPa) contribuent à une bonne résistance à l'usure et faible coefficient de frottement (< 0.2). Ces films sont élaborés en PACVD basse fréquence (f = 50 KHz – DC bi...
