The Engineer

Solar-cell producer validates Natcore AR coating process

News

An antireflective (AR) coating process from US-based Natcore Technology has been independently validated by a prominent Chinese solar-cell manufacturer.

Several silicon wafers with antireflective coatings prepared by Natcore’s researchers at Ohio State University were supplied to a Chinese government-selected solar-cell manufacturer for cell finishing and testing.

The wafers were coated using Natcore’s liquid phase deposition (LPD) technology. Originally developed at Rice University and now licensed by Natcore Technology, the process has the advantage that the anti-reflective (AR) layer of a solar cell can be produced in a mild chemical bath.

Current thermal oxide technology used for the same purpose requires relatively thick silicon wafers because of the high heat involved and thinner wafers often warp in this harsh environment.

The validating company - Hunan TLNZ Solar Technology - first analysed the composition and quality of the Natcore-supplied films, then added metal front and back contacts to the cells and tested their efficiency.

Cell efficiencies as high as 15 per cent were measured using actual production solar cells.

The results demonstrated that Natcore’s LPD AR coating technology is compatible with standard silicon solar-cell production methods and can be integrated into existing solar-cell manufacturing facilities.

The validating company also identified the process steps to be included in a commercial production system that will enable cells using Natcore’s AR coating technology to be produced that reach or exceed 17 per cent efficiency in production.

’This is a major step on the way from the lab to the marketplace,’ said Natcore president and chief executive Chuck Provini. ’Just as we anticipated, our efficiencies will equal or exceed efficiencies from cells produced using conventional means. But we’re doing so at a significantly lower cost - and without using high-temperature vacuum furnaces, toxic silane or huge amounts of silicon, and without the environmental damage created by the old chemical vapour deposition method. We’re replacing the CVD method with our LPD wet chemistry process.’