Schott Solar Joins IMEC Silicon PV Program
Schott Solar has joined IMEC's newly launched silicon photovoltaics industrial affiliation program (IIAP) with a three-year research partnership. Through the IIAP, researchers from Schott Solar will focus on developing solutions for next-generation silicon-based solar cells.
Staff -- PV Society, 6/4/2009
Schott Solar (Alzenau, Germany) has joined the newly launched silicon photovoltaics industrial affiliation program (IIAP) at IMEC (Leuven, Belgium) with a three-year research partnership. Through the IIAP, researchers from Schott Solar will focus on developing solutions for next-generation silicon-based solar cells. "In the highly dynamic market of solar power, short time-to-market for new products is essential," said Martin Heming, CEO at Schott Solar.
Within this multi-partner R&D program — including solar cell manufacturers, and equipment and material suppliers — IMEC aims to explore and develop advanced process technologies to fuel the steep market growth of silicon solar cells in a sustainable way. The program will concentrate on a sharp reduction in silicon use, while increasing cell efficiency and further lowering the cost per watt peak.
Within the program, IMEC aims to reduce both the cost of producing crystalline silicon (c-Si) solar cells and the amount of silicon per watt that is needed by half. The program will explore both wafer-based bulk silicon solar cells and epitaxial cells.
Within the bulk-silicon solar cell sub-program, generic process technology crucial for increased efficiency and manufacturing cost reduction will be developed. The active silicon layer thickness will be reduced from 150 µm down to 40 µm. To meet efficiencies of ~20%, alternative back-side dielectric stacks and interdigitated back-side contacts (i-BC) will be introduced in thin wafers using a PERL-style (passivated emitter and rear local back surface field) concept in an industrial process flow.
Cell module integration will be investigated, since reduced wafer thickness will impose specific integration requirements. As the guaranteed lifetime of cells and modules will further increase in the next decade from 20-25 years up to 35 years and more, reliability will also be assessed in depth. And new methods to realize and handle wafers as thin as 40 µm will be pursued. The potential of the technology will be benchmarked in small area lab cells and large-area solar cells.
Besides the generic bulk silicon research that is relevant to c-Si solar cell technology, epitaxial thin-film (<20 µm) silicon solar cells on low-cost silicon carrier will also be developed. Epitaxial thin-film silicon solar cell technology is expected to be the intermediate step before mainstream fabs will switch from bulk silicon solar cells to thin-film solar cells. The process is generically similar to the bulk process and the epi process can be implemented with limited equipment investment. To improve the optical confinement of light in the active part of the cell, a buried porous silicon reflector will be developed.
