Simple analytical model and efficiency improvement of polysilicon solar cells with porous silicon at the backside

The present study developed a simple analytical model to simulate the performance of polysilicon solar cells with porous silicon (PS) layer at the backside. It analytically solved the complete set of equations necessary for the determination of the photocurrent generated under the effect of the reflected light. It also investigated the contribution of the light absorbed by the PS layer and explored the effect that the latter’s number of double porosities and high porosity have had on photovoltaic parameters. The findings suggest that the photovoltaic parameters increase with the number of double porosities that the layer might have in a given structure. When the PS layer is formed by three-double porosity layers 20%/80% and for a 5 μm-thick film c-Si, the backside reflector gives a total improvement of about 2.65 mA/cm² in photocurrent density and 1.4% in cell efficiency. This improvement can even be of much more important for well passivated grain boundaries and back contact of solar cells.