IMEC, one of the leading European research centers in photovoltaics, and BP Solar, a leading energy company, demonstrated a 18% conversion efficiency for silicon solar cells made of BP Solar’s newly developed Mono2TM silicon. By combining IMEC’s advanced processing techniques with BP Solar’s high-quality low-cost substrates, the companies demonstrated that Mono2 has a good potential to become a new base material for low-cost highly-efficient solar cells.

BP Solar’s Mono2 production process delivers a promising new wafer platform for solar cells with the potential to become a low-cost alternative to the more expensive Czochralski silicon substrates because it combines extremely low defect densities and high conversion efficiencies with production costs that are comparable to the costs of traditional multicrystalline substrates. The production of Mono2 involves a proprietary growth nucleation process for the casting of ingots used to produce single crystal bricks and wafers whereby preferred crystallographic orientations can be achieved. This feature allows further improvement in cell efficiencies. BP Solar’s Mono2 was developed with support of the U.S. Department of Energy’s Technologies Pathways Partnership.

IMEC’s cell production process is feasible as an industrial production process as it only adds three processing steps to the standard industrially applied process of full aluminum back surface field.

IMEC’s solar cells are 130μm thick and cover an area of 156mmx156mm. Using IMEC’s advanced processes such as dielectric passivation and a localized back surface field, a conversion efficiency of 18% for the new low-cost Mono2 silicon solar cells, which is in the range of the current commercial solar cells, has been demonstrated with a dramatic reduction in cell thickness.

Jef Poortmans, Program Director Photovoltaics said, “IMEC’s photovoltaic research aims towards a sharp reduction in production cost and at the same time an increase of the efficiency of crystalline silicon solar cells. Our partners can leverage our advanced processing techniques, to create high-efficiency low-cost solar cells based on their proprietary high-quality materials and knowhow.”

Eric Daniels, BP Solar’s vice president, global technology said “BP Solar is working to leverage such key technology developments to further reduce the cost of PV electricity. Working with R&D centers such as IMEC and key customers, we are commercializing this technology and seek to provide a better platform for the current and next generation solar cells. This collaboration with IMEC represents significant progress towards that goal.”