While the cost benefits of technology improvements in bulk crystalline silicon wafers and economies-of-scale have seemingly plateaued, this project aims to investigate improvements to device performance and reduced manufacturing costs while delivering high production yields for solar cells.

Probably the most promising technology component of a solar cell is the selective emitter, which achieves efficiency of 19 per cent using standard p-type or n-type commercial mono-silicon wafers.

As part of this project the UNSW in collaboration with Suntech R&D Australia will further develop the selective emitter technology, and apply similar principles and high efficiency attributes to the rear surface design of devices. New performance records are anticipated for standard CZ wafers although perhaps more importantly, the new technology will be compatible with low cost multicrystalline silicon wafers. This is expected to eventually achieve efficiencies approaching 20 per cent following successful pilot production efficiency of 17 per cent. Of key importance is overcoming the degrading effect of pro-longed high temperatures on low-cost wafers by using inkjet technology and a laser to apply the necessary heat for localised formation of heavily doped regions. This means the remainder of the wafer isn’t subjected to high temperatures and avoids the associated problems.

This project aims to achieve this by addressing the remaining major source of cell performance limitation – recombination of photo-generated current carriers at the rear surface.

Working with its industry partners in this project, UNSW will update its semiconductor finger (SCF) process and investigate the advantages of LIP metallisation. Subsequent stages of the project will look to eliminate rear surface recombination by investigating a variety of surface passivation and point metal contacting schemes, building on the PERL (Passivated Emitter Rear Locally diffused) cell structure developed by UNSW over many years of research.

In addition, this program will look to investigate possible increased efficiencies in the PERL solar cell, potentially opening up new avenues for cost effective industrial manufacturing.

Fact sheet: Overcoming the fundamental performance limitations of commercial solar cells (PDF 303KB)