EpiSil-IBC · Epitaxial silicon foil solar cells with interdigitated back contacts

Epitaxial silicon foil solar cells with interdigitated back contacts

The leading technology in the photovoltaic market today is the single junction crystalline silicon (c-Si) solar cell. Since there is little room for further improvement beyond current efficiency records the industry is focused on reducing manufacturing costs. To reduce material costs the c-Si technology is pushed towards thinner and thinner cells, which are harder to handle without breaking. One way to make thin solar cells without kerf losses is to grow the silicon foil epitaxially on a parent wafer followed by a lift off step. Since such thin foils are mechanically very fragile, new processing techniques are required in which the foils are bonded to a glass substrate, such that they are never handled free-standing. Such new device concepts directly contribute to the competitiveness of low-carbon energy production and therefore support the EU’s climate and energy goals to reduce greenhouse gas emissions by 20% below 1990 levels by 2020 and provide 20% of EU energy from renewable sources. The advantage of the epitaxial growth is that it can directly grow crystalline material from the precursor gas which has the potential to produce cheaper and higher quality wafers and foils, providing new market opportunities for European companies and making the transition to low-carbon society economically even more stimulating. The aim of this proposal is to realize a solar cell based on ultra-thin (<50 μm) silicon foils bonded to glass and with all contacts on the back side of the cell. The goal of this innovative solar cell is to surpass the current state-of-the art efficiencies of thin silicon foil solar cells by using low-cost and high yield processing.

Data: CORDIS, © European Union