Completed project: Next generation photovoltaics

The image shows the sun in the sky with clouds.

The main objective of this project was the development of highly efficient next generation photovoltaic technologies. Through the integration of simple perovskite, c-Si and CIGS cells with improved optoelectronic characteristics in tandem cells, it was possible to achieve globally unprecedented levels of efficiency.

Technologies and photovoltaics based on crystalline silicon (c-Si) and copper indium gallium selenide (CIGS) are presumably only a first step towards utilising solar energy as a main power source, as they are inefficient in converting high-energy photons. A higher electricity output can be achieved by using a tandem cell with an upper cell that has a higher band gap.

The research team of Prof. Christophe Ballif from the Institute of Microtechnology of the EPF Lausanne spanned the synthesis of novel materials, their integration in high-efficiency single- and multi-junction solar cells with c-Si and CIGS, the development of solar façade concepts, grid management strategies and analysis of the life cycles and social acceptance of these new technologies.


Combining advanced simulation and characterisation techniques with thin film processing, the project team was able to design perovskite, c-Si as well as CIGS single-junction solar cells with improved optoelectronic properties. By combining them in multi-junction devices, the project partners were able to achieve world record efficiencies, notably the first perovskite/c-Si tandem featuring a texture on the front side for optimal light management, or flexible thin film perovskite/CIGS 4-terminal tandems. In parallel, the project contributed to improving the acceptance of PV installations, particularly by working on strategies aimed at minimising space usage and by improving efficiencies and promoting building integration on the basis of aesthetic solutions.