This project applies proprietary, silicon-on-sapphire manufacturing technology
to form solar cells that sustain high levels of electrical performance over
system lifetime, while lowering cell and system manufacturing costs.

The project aims to lower solar energy costs by improving the efficiency of solar cells through novel cell designs and manufacturing technologies and lowering system costs through the use of robust, environmentally stable substrates.

Initially, this project will focus on achieving specific efficiency targets in single-crystal, thin-film silicon solar cells. Then the project team will continue to develop and commercialise high-efficiency, thin-film, silicon and multi-junction solar cells on sapphire substrates.

To achieve these outcomes, several challenges must be overcome. First, a mature, silicon-on-sapphire integrated circuit manufacturing technology must be adapted to produce solar cells. This will require the modification or elimination of many process steps, the adoption of thicker silicon layers and the simplification of the manufacturing flow so as to reduce cost. Second, light trapping structures, including anti-reflective films and twodimensional Bragg gratings, must be developed and integrated into the siliconon- sapphire manufacturing process flow. Finally, novel cell architectures that exploit the unique characteristics of the silicon-on-sapphire platform must be implemented and optimised.

The planned approach offers many potential benefits. First, the substrate and active device enables a highly effective light trapping solution because of the difference in the refractive index. Second, the long carrier lifetimes in the high quality, single-crystal solar cells enable photogenerated carriers to be quickly collected before they thermalise, increasing conversion efficiencies. Third, single sided cell architectures eliminate shadowing and enable highly effective cooling solutions. Finally, the robust, environmentallystable substrate eliminates the need for additional protection and encapsulation layers, reducing system cost.

Fact sheet: A high efficiency, integrated solar module on a transparent substrate (PDF 277KB)

Project report: A high efficiency, integrated solar module on a transparent substrate (PDF 149KB)