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State-of-the-art Development of Solar Energy Materials and technologies: PV – CPV - CST

The panorama of solar technologies includes a series of devices based on diversified materials, photo-conversion processes, efficiencies, and costs. Depending on the end-user application, various technology platforms are available. Besides the mature field of silicon solar cells, in photovoltaics (PV), thin-film technologies including chalcogenide semiconductors, amorphous/micromorphous silicon, and nano/micro/poly-Si are fast becoming highly interesting to the market, thanks to their outstanding functionality in integrated devices. Other emerging technologies are represented by perovskite solar cells, and organic and quantum dot solar cells, which offer increasingly high photoconversion efficiency, while maintaining highly competitive costs, with interesting progress toward device stability, mainly based on tailored materials fabrication.  New physical effects are also investigated to push the photoconversion efficiency such as intermediate bands, multiple exciton generation, hot carriers, and up/down conversion. The success of the above emerging and prospective solutions calls for the availability of reliable materials systems
Concentrated photovoltaics (CPV) based on III-V multi-junction solar cells and of optics to concentrate solar light may reach the highest efficiency and lower energy payback time of all photovoltaic technologies today available and with module conversion efficiency over 40%.  Howerer its large-scale entry into the market is hampered by the higher manufacturing and operational costs compared to silicon photovoltaics. Therefore, interest in CPV shifted towards the design of new system architectures either for low-power density applications such as luminescent solar concentrators (LSCs) based on new inorganic (quantum dots) or organic (carbon dots) luminophores, which are highly interesting for applications such as the so-called building integrated photovoltaics (BIPV) or greenhouse technologies, or to realize high power density CPV modules, including Micro-CPV architectures, required by the fast-growing markets of space-restricted applications such as vehicle-integrated PVs, space solar, mobile chargers, off-grid power systems, robotics and other.
Concentrating Solar Thermal (CST) technology is the focus of intense research and development activities worldwide due to its potential in generating renewable energy and decarbonising industrial processes and it is expected to contribute significantly to future sustainable energy mix.
As a renewable source of electricity, CST uses the energy generated by concentrated solar radiation to power a steam or a gas turbine; or else, the heat produced can be appropriately stored for off-sun electricity generation at a lower cost than traditional batteries utilized in PV systems. Moreover CST can be used for the production of hydrogen, fuels or chemicals by high temperature “green” processes and for decarbonation of industrial cycles.
A main challenge for increased system efficiency is to achieve operating temperatures to exceed 1000 °C which implies increased demands on structural materials and coatings for their thermomechanical and chemical stability, reliability and lifetime. Moreover, advances in functional properties in optical materials for absorbers and reflectors are critical for efficiency improvements and cost reductions. Heat-resistant materials with higher stability and storage capacity and appropriate thermal transport properties are required for thermal storage systems, whereas improved materials are on demand to drive small-scale thermochemical reactions such as water splitting, hydrogen and fuel production, and for industrial decarbonation.
This symposium aims to bring together experts of diverse backgrounds to present latest research results and debate challenges, ongoing developments and perspectives for competitiveness, efficiency, reliability and safety of PV, CPV and CST technology in their broad application fields.