Energy

Silicon solar cells

Highly efficient crystalline silicon solar cells – Imec works on reducing the thickness of the active silicon layer from 150μm down to 40μm. This will substantially lower the production cost of crystalline Si solar cells.

To reach efficiencies of more than 20% on such large-area thin wafers, imec has introduced alternative back-side dielectric stacks using a PERL-style (passivated emitter and rear local back surface field) passivation, and interdigitated back-side contacts (i-BC), both in an industrial process flow.

We also investigate the integration of these new cells in modules, as reduced wafer thickness will impose specific integration requirements. And we work on and asses the reliability of the cells, as the cells will need a guaranteed lifetime of up to 25 years.

Thin-film crystalline-silicon solar cells – Imec also develops epitaxial thin-film (<20μm) silicon solar cells grown on low-cost silicon carriers.

The process to fabricate such epitaxial thin-film cells on low-cost silicon carriers is generically similar to the bulk process, so an epi-process can be implemented with limited equipment investment in existing manufacturing lines.

To improve the optical confinement of light in the active part of such cells, we work on buried porous Si reflectors.