AN UNSW-developed solar panel processing technology has resulted in a collaboration between Suntech Power and Hanwha Solar.
The two photovoltaic manufacturers were interested in the technology from the UNSW School of Photovoltaics and Renewable Energy Engineering (SPREE), whereby tiny metal contact regions can be “self-patterned” into a solar cell’s electric insulator, which rests between the silicon wafer and the aluminium back-plate.
“Currently closely-spaced small-area metal contact regions in an insulating layer can only be formed by deliberately patterning the holes with a laser scanning over the surface, which is quite slow,” says Dr Alison Lennon, a senior lecturer from SPREE.
“Other methods, such as aerosol and ink-jet printing, have been explored, however currently these methods are currently too slow and have not been able to demonstrate the required patterning reliability.”
Lennon and her PhD students are investigating a radical approach to automate and quicken this patterning using aluminium anodisation, a well-understood process where a chemical coating is formed on a metal surface to protect against corrosion.
When aluminium is anodised, a porous insulating layer is formed on it. This effectively turns an aluminium layer on a silicon solar cell into a dielectric layer with lots of little holes.
The UNSW team has made prototypes of cells using this technique, and are now working on understanding how the metal contacts form in order to improve cell efficiencies, and refining the technique so it can produce competitive results on an industrial scale.