PROCESS DEVELOPMENT OF LASER GROOVED BURIED CONTACT SOLAR CELLS FOR USE AT CONCENTRATION FACTORS UP TO 100X

The efficiency limitations for low cost Laser Grooved Buried Contact (LGBC) silicon solar cells for concentration factors up to 100X have been modelled using a combination of a front contact model developed in-house and PC1D [1]. Cells have been designed to suit customer requirements with different concentrator system geometries and a range of concentration factors. Cell efficiencies of 18.9% and 18.5% at 20X and 30X respectively were achieved on Cz silicon cells of 40cm active area, while for cells of 2.6cm active area, efficiencies of 19.3% at 50X and 18.7% at 100X were obtained. Good uniformity of cell efficiency from across a large area wafer has been achieved. The limiting factors on concentrator cell efficiency is presented and ways to achieve 20% efficiency at 100Sun is discussed.