Due to their fascinating optical and electronical properties, nanometer-scaled structures play an important role in solar energy conversion. In our research group at EPFL’s Solar Energy Laboratory LESO-PB, we develop novel micro- and nanostructured smart materials for active and passive solar energy applications being integrated into the building envelope. We focus on thin films, because these allow covering a large surface area with a small quantity of raw material – and we focus on their electronic and optical properties, because these closely interrelated properties are most important for the utilisation of solar energy.
Nanocomposite coatings consist typically of dielectric, semiconductor or metal nanocrystals being embedded in a dielectric matrix. Effective medium theories such as the Bruggeman and the Ping Sheng theories are used to model the dielectric function of nanocomposite materials. Micro- and/or nanostructuring materials can result in very interesting features such as tuneable band-gaps by quantum confinement, adjustable complex dielectric function, enhanced mechanical stability, superhydrophobicity, frequency-selective surfaces FSS, etc. The semiconductor-to-metal transition observed in transition metal oxides with strong electron correlations can be exploited for smart switching coatings.
The scope of envisaged solar energy applications is large. Recent work focuses especially on smart materials, such as thermochromic selective solar absorber coatings for overheating protection of solar thermal systems, and electrochromic coatings for switchable windows. Further applications include novel microstructured glazing with strong seasonal dependence of the solar heat gains, photoluminescent quantum dot solar concentrators for photovoltaic energy conversion, antireflection coatings on solar collector glazing, colored coatings with high solar transmittance for novel glazing of photovoltaic facades, selective solar absorber coatings for thermal solar collectors and thermoelectric power generation, as well as novel insulating glazing with high transmittance for the microwaves of mobile communication.
- Optical coatings on solar glass for photovoltaic modules and solar thermal collectors – development of colored glazing for solar facades and solar roofing
- Solid-ion-conductors for durable electrochromic windows
- Metallic micro-/nanomeshes for transparent conductive layers
- Nanostructured low refractive index materials on solar collector glazing
- Smart selective solar absorber coatings based on reversible semiconductor-to-metal transition
- Optical microstructures for advanced architectural glazing
- Energy efficiency of public transportation
- Frequency-selective surfaces by nanosecond laser-ablation
- Angular dependent optical and thermal properties of advanced architectural glazing
- Highly durable selective solar absorber coatings for solar thermal collectors and electricity generation by concentrated solar power (CSP)
- Quantum dot solar concentrators for building integrated photovoltaics
WO2017134589 (A1) : Coating for optical and electronic applications – Single- or multilayered coating, such as a selective solar absorber coating or a coating being part of an integrated electronic circuit, comprising one or more layers containing germanium (Ge) doped VO2+x, where -0.1 ≤ x ≤ 0.1.
Krammer Anna, Paone Antonio, Schüler Andreas
PCT/IB2017/051952: Solar cooker
Mauree Dasaraden, Schueler Andreas, Diévart Alexandre, Bouvard Olivia
WO 2014045141 A2: Laminated glazing with coloured reflection and high solar transmittance suitable for solar energy systems
Le Caër Hody Virginie, Schüler Andreas (Déposant SwissInso SA)
WO 2014045144 A1: Interference filter with angular independent orange colour of reflection and high solar transmittance, suitable for roof-integration of solar energy systems
www.glassdbase.ch – an independent and comprehensive building glass database set up by University of Basel, Switzerland and now managed by LESO-PB
Bouvard Olivia, Scartezzini Jean-Louis and Schueler Andreas (Dirs.). Coatings with tailored electronic and optical properties for advanced glazing. EPFL Thesis n° 9199 (2019)
Microstructured glazing for daylighting, glare protection, seasonal thermal control and clear view. EPFL PhD thesis, n° 6465 (2015)
A. Paone, J.-L. Scartezzini and A. Schueler (Dirs.). Switchable Selective Absorber Coatings for Overheating Protection of Solar Thermal Collectors. EPFL PhD thesis, n° 5878 (2013)
Développement et optimisation de revêtements minces nanostructurés pour capteurs solaires thermiques et modules photovoltaïques. EPFL PhD thesis, n° 5541 (2012).
RailTech 2019 Innovation Award, Utrecht, to Andreas Schüler, Olivia Bouvard, Luc Burnier, Jérémy Fleury, for Energy efficient windows that transmit telephone signals.
Watt d’Or 2019 “Energy efficient mobility” by Swiss Federal Office of Energy, Andreas Schüler, Olivia Bouvard, Luc Burnier, Jérémy Fleury (as part of a team headed by BLS train company and Basel University), for Nina trains energy efficiency modernisation. Contribution: energy efficient windows transparent to phone signals.
Award winning publications
Jing Gong, André Kostro, Jean-Louis Scartezzini, Andreas Schüler, Feasibility study on a novel daylighting system with embedded micro compound parabolic concentrators (CPCs). Nonimaging Optics: Efficient Design for Illumination and Solar Concentration XV (Vol. 10758, p. 1075807). International Society for Optics and Photonics. Nonimaging optics best paper award – SPIE Optical Engineering & Applications, 2018, 19-20 August 2018, San Diego, CA, USA
Martin Joly, Yan Antonetti, Martin Python, Marina Gonzalez, Thomas Gascou, Jean-Louis Scartezzini, Andreas Schüler, Novel black selective coating for tubular solar absorbers based on a sol-gel method, Solar Energy Journal Best Paper Award 2012-2013
Peter Oelhafen, Andreas Schueler, Nanostructured materials for solar energy conversion, Solar Energy Journal Best Paper in Energy Conversion Award 2005/2006