Ce chapitre explore la filière photovoltaïque basée sur le silicium cristallin, qui domine le marché avec plus de 90 % des cellules solaires produites. Il aborde les différentes formes de silicium (monocristallin, multicristallin, polycristallin et amorphe), leurs propriétés et leurs applications. La chaîne de valeur industrielle est présentée, depuis l’extraction et la purification du silicium (procédé Siemens) jusqu’à la cristallisation (méthodes Czochralski et Bridgman), la découpe des lingots en plaquettes, et la fabrication des cellules solaires. Les technologies clés comme les cellules Al-BSF, PERC, IBC et à hétérojonction sont détaillées, mettant en lumière leurs avantages en termes de rendement et d’efficacité. Le chapitre traite également de l’assemblage des modules photovoltaïques, incluant l’encapsulation, les innovations comme les modules bifaciaux, et les pertes optiques et électriques. Enfin, il discute des facteurs limitant le rendement (recombinaisons, pertes résistives) et des perspectives d’amélioration, comme la passivation des surfaces et les architectures tandem.

Surface tension-driven self-alignment is a promising technique to align millimeter-scale components with a high accuracy of a few microns. It is based on liquid capillary forces moving and aligning a solid component on its receiving pad. Using molten solders as the liquid is a promising way to bond, connect and align a chip with its substrate. Micro-solar cells soldering experiments for micro-concentrator photovoltaics have been carried out. It has been found experimentally that the solder volume, the receiving pad size and the initial placement of the chip have an impact on the placement accuracy. In this work, an analytical and a numerical model of the capillary forces during self-alignment are built to improve the understanding of the experimental results. Guidelines to reach a high placement accuracy are presented. In practice, low solder volumes, receiving pads smaller than the chip and an initial chip displacement of about 10% of the chip size yield a higher placement accuracy. 2023-0153

In this work, we comprehensively review Mie resonator-based and nonlocal resonant metasurfaces working in the reflection configuration for color printing applications, with particular attention to high observation angle applications. While Mie resonator-based metasurfaces are found to be simple to design and present low sensitivity to the observation angle, they present the drawback of low color saturation. By contrast, square lattice photonic crystal waveguide-based metasurfaces show very selective spectral responses, yielding pure colors but with high selectivity on the observation angle. In order to harness the exceptional color-filtering properties of photonic crystal waveguides and maintain the desired spectral response under oblique angles of observation, a rectangular lattice for the crystal structure is proposed. We provide design rules and examples in order to produce angularly robust, vivid colors at any desired wavelength within the visible spectrum. Furthermore, by exploiting the polarization of the incident light and adapting the design of the photonic crystal structures, we demonstrate color multiplexing for cryptography applications.

Concentrator photovoltaics is a promising solution to power space missions at a low cost and also for deep missions. Micro-concentration allows to increase the specific power of the concentrator, reducing its mass and weight compared to standard concentration. This work presents the manufacturing process of the first prototype of a highly integrated micro-concentrator design. Manufacturing tolerances are characterized and the associated optical losses are assessed. The specific power is estimated to 328–390 W/m 2 . A first electrical characterization of a prototype with one solar cell is presented. A solar conversion efficiency of 21% was reached with outdoor measurements.

In this paper, the effect of the integration of Phase Change Material panels for summer thermal comfort and cooling demand of a classroom under warm temperate climate was numerically assessed. The PCM panels are fixed on the internal faces of the walls (east, west and south) and roof. They are modeled using TRNSYS software, specifically Type 339. A comparison before and after using PCM on the roof and the east, west and south walls as well as on the combination wall-roof was undertaken. The results showed that the cooling demand was reduced from 6.8 kWh/m2/year to 5.5 kWh/m2/year with the combined roof-wall configuration of PCM compared to the initial case. Indoor temperature was reduced by 1.13 ℃ for the roof-wall configuration. Moreover, with regard to the thermal comfort standard that requires an indoor temperature between 21 ℃ and 27 ℃, this combination reduced the discomfort hours by 25% comparing to the base case.

Photovoltaic solar cells are designed to efficiently absorb solar photons but convert only a limited proportion of them into electricity. Under real operating conditions, the remaining energy causes solar modules to heat up to 50–60 °C, which is detrimental to their power conversion efficiency and lifetime. In recent years, there has been a growing interest in the so-called radiative sky cooling strategy. This approach consists in optimizing the thermal radiation of cells or modules—with the help of photonic structures—by taking advantage of the atmospheric transparency in the 8–13 range. In this paper, we present an in-depth analysis of radiative sky cooling applied to silicon based photovoltaic modules. A simulation of a preliminary design of a photonic structure for possible radiative sky cooling of a module is also proposed.

Light Management (LM) is essential for metal-halide perovskite solar cells in their race for record performance. In this review, criteria on materials, processes and photonic engineering are established such as to enhance mainly the short circuit current density, towards high energy yields. These criteria are used to analyse a large panel of solutions envisaged in the literature for single junction cells. Moreover, a perspective based on rigorous electromagnetic simulations performed on various comparable structures is proposed in order to clarify the conclusions, and to pave the way to further performance enhancement in the case of all-perovskite, two-terminal tandem cells.

This paper presents a numerical study combining different passive measures to improve the energy efficiency of a building. These measures include night ventilation and physical design such as building materials, thermal insulation as well as window configuration combined with winter and summer solar shading. The study focuses on a basic classroom prototype that complies with the Algerian buildings. It took the city of Constantine in Algeria as a case study for the warm temperate climate of the Mediterranean regions. The results show that adopting such passive measures reduces the building's energy demand from 67.5 to 15.7 kWh/m2 for heating and from 7.7 to 5.7 kWh/m2 for cooling. This leads to an annual reduction of 53.8 kWh/m2, or an energy saving of 72% per year. Furthermore, CO2 emissions were reduced by 72% passing then from 1772 to 499 kg/year. Thus, a correlative reduction between energy demand and carbon footprint is observed. The economic analysis shows that life cycle costs are influenced by energy prices in different countries and that the profitability of these measures strongly depends on whether these prices are subsidised or not.

Photovoltaic (PV) solar cells are designed to efficiently absorb solar photons but convert only a limited proportion of them into electricity. The remaining energy is converted into heat, which in turn, heats the entire solar modules up to 50-60 °C under real operating conditions. This is detrimental to both their power conversion efficiency and lifetime. Recently, there has been a growing interest in the so-called radiative sky cooling (RSC) strategy. This approach consists in optimizing the thermal radiation of cells or modules - with the help of photonic structures - by taking advantage of the atmospheric transparency in the 8-13 μm range. Although some basic studies predict cooling of more than 10°C on silicon devices, they remain insufficient to assess the potential of this technique for various PV technologies directly from their material properties. Using COMSOL Multiphysics, we are working on a fully coupled model of silicon solar cells in order to predict their opto-electro-thermal behaviour from the bottom-up (i.e. using only material properties as an input). This enables us to study various photonic pathways for enhanced radiative sky cooling. Our work also shows the importance of moving towards fully coupled models to accurately predict the temperature and electrical output under real conditions.

A few tens of nanometre thick ultrathin materials may suffer from a very low absorption at their band edges. In this work, we investigate a photonic crystal (PC) made of a lowcost, transparent patterned silicon nitride (SiNx) layer, conformally covered with an ultrathin active layer (e.g., 20 nm TiO2) in view of its use in various applications such as photocatalysis. A fair estimation of the absorption enhancement, considering the volume of the active material, is calculated using RCWA. A remarkable enhancement (more than ten-folds) in absorptance in the near UV range and a very high transmittance over the visible range are observed. A detailed modal analysis of the structures-of-interest unravels the Light Trapping (LT) mechanisms and allows the derivation of key design guidelines. Optical measurements on a patterned sample provide a first proof-of-concept of such possible photonic backbone structures suitable for highly efficient depollution and artificial photosynthesis for solar fuels production.

A novel photovoltaic microconcentrator design for space is developed, in which the optical elements are integrated into a honeycomb and solar cells are located on a glass substrate to face the optics. The final structure is composed of two stacked sandwiches of different materials and sizes. The purpose of this study is to assess the mechanical behavior of this structure under bending loads in order to optimize the design of the microconcentrator structure to meet space specifications. Taking the influence of the thermal vibrations of the structure on the optical performance into account, the maximum length of the solar panel assembly is estimated. To do so, four-point bending tests were performed on six variations of the design. Then, an analytical and two finite-element models of the bending tests were implemented and the results were compared with the experiments. The friction between the test fixture and the samples proved to induce an overestimation of the bending stiffness by up to 34%. In the end, the bending stiffness per unit of mass and the stress distribution of the structures were assessed to determine the most interesting variations of the design. The glass should be the thinnest possible depending on the stress relative to the mission of choice for the spacecraft. The bottom honeycomb should be thick to increase the stiffness. The bending stiffness target of $5\times 10^{6}\text{N}\cdot \text{mm}^{2}$ and the acceptance angle of 4.2 $^\circ$ limit the solar panel assembly length to 8 m.

In this work, a fully coupled opto-electro-thermal model for crystalline silicon solar cells is presented. Based on a detailed set of material properties, the developed model allows us to predict and analyse the solar cell behaviour under real operating conditions in a standalone framework. The results show the potential of our model to study the influence of the cell design on its real operating performance, thus giving a new opportunity for silicon solar cell optimisation. Specifically, the doping level is found to impact both the operating temperature and the temperature coefficient, showing that two cells with the same power conversion efficiency in standard test conditions can have a very different efficiency under real operating conditions. We also demonstrate the model capability to assess in detail the influence of environmental conditions, such as the solar spectrum, which also impacts the temperature coefficient. As the latter is not required by our material-based approach but is a simulation output, this work opens the way to more reliable outdoor prediction. Moreover, the various perspectives and challenges associated with the proposed detailed multiphysics simulation of solar cells are discussed, providing important guidelines for future studies.

Exciton‐polaritons are mixed light–matter excitations resulting from the strong coupling regime between an active excitonic material and photonic resonances. Harnessing these hybrid excitations provides a rich playground to explore fascinating fundamental features, as out‐of‐equilibrium Bose–Einstein condensation and quantum fluids of light, plus novel mechanisms to be exploited in optoelectronic devices. The formation of exciton‐polaritons arising from the mixing between hybrid inorganic–organic perovskite excitons and an optical bound state in a continuum (BIC) of a subwavelength‐scale metasurface, are experimentally investigated at room temperature. These polaritonic eigenmodes, hereby called polariton BICs (pol‐BICs) are revealed in reflectivity, resonant scattering, and photoluminescence measurements. Although pol‐BICs only exhibit a finite quality factor bounded by the nonradiative losses of the excitonic component, they fully inherit BIC peculiar features: a full uncoupling from the radiative continuum in the vertical direction, which is associated to a locally vanishing farfield radiation in momentum space. Most importantly, the experimental results confirm that the topological nature of the photonic BIC is perfectly transferred to the pol‐BIC. This is evidenced by the observation of a polarization vortex in the farfield of polaritonic emission. The results pave the way to engineer BIC physics of interacting bosons and novel room temperature polaritonic devices.

In this work, we study the dynamic temperature-dependent performance of perovskite solar cells (PSCs) and propose a full model to predict its energy yield (EY) under realistic conditions. This model stands out for the inclusion of a robust thermal model which allows to estimate the cell temperature from given meteorological conditions. Linking the experimental electrical and optical dependence of PSCs and the thermal model we analyze the most sensible layers that increases the device temperature. Finally, we evaluate the EY of PSC working on different geographical locations and show that the impact of temperature on this prediction can be more than 10 %.

Photovoltaic (PV) solar cells are designed to efficiently absorb solar photons but convert only a limited proportion of them into electricity. The remaining energy is converted into heat, which in turn, heats solar modules up to 50-60 °C under real operating conditions [1] , which is detrimental to their power conversion efficiency and lifetime. In recent years, there has been a growing interest in the so-called radiative sky cooling (RSC) strategy. This approach consists in optimizing the thermal radiation of cells or modules - with the help of photonic structures - by taking advantage of the atmospheric transparency in the 8-13 μm range [2] , [3] . Although some preliminary studies on the subject predict cooling of more than 13°C on silicon wafers [4] , they remain insufficient to fully assess the potential of this technique for various cell and module technologies.

Many applications require colored surfaces while maximizing photons to pass through with no optical losses. As the perceived color depends on the spectral content and the number of reflected photons for each wavelength, it is necessary to consider not only the chromatic content but also the brightness. As a first application example, photovoltaic modules could see their acceptance in urban situations greatly improved if their color could be controlled while maximizing the number of photons used for energy conversion. In this case, it is important to limit light brightness to avoid glare when light coming from the sun is reflected directly. As another example, a colored and semi-transparent glass layer in the infrared could efficiently protect sensors while camouflaging them, such as lidar in automotive applications. We propose a theoretical study for multicolor applications, considering 2D partially etched grating waveguide structures that behave as a perfect broadband antireflection coating while the residual layer couples light in a waveguided mode in order to reflect only a particular photon band. This strategy allows to produce a large variety of colors and the use of non-absorbing materials avoids any optical loss. The width of the resonance peak is a crucial parameter for balancing brightness in multicolor applications. In the second part, we developed a method for a fast optimization of the geometrical parameters and we applied it to obtain the three primary colors with strong geometrical constraints, so that such structures could be manufactured in a single step by nanoimprint. Finally, we propose some improvements of these structures, in particular by reducing broadband reflection to obtain more saturated colors, or to improve the angular behavior of these structures. (C) 2021 Society of Photo-Optical Instrumentation Engineers (SPIE)

This work focuses on the experimental study of a standard dwelling and a high energy performance dwelling, located in the city of Djelfa in Algeria whose climate is semi-arid, in order to study their thermal performance for 12 months. The high energy performance dwelling was built as part of the pilot project of 600 dwellings in 11 locations spread all over the different climatic zones in Algeria and the first to be finalised compared to the other locations. According to measurements, the temperature and the relative humidity were maintained in the thermal comfort range with the use of electricity for air-conditioning and the natural gas for heating. The results indicate that the reduction of heating demand is 57% and of air-conditioning is 51% by using the passives energy efficiency techniques in the buildings. In order to improve the economic profitability of the thermal insulation, new correlations were used for the payback period and financial profits realised that can be achieved in countries that subsidise energy. It was found that depending on the assumed correlation on the energy used, the investment in thermal insulation and double glazed window can be profitable from a payback period of 4 years or less.

A fundamental modelling framework of solar cells is presented in order to quantify the potential benefit of enhanced radiative sky cooling for different single-junction technologies, according to their basic electrical and thermal properties.