Modeling of polycrystalline N+/P junction solar cell with columnar cylindrical grain

Abstract

Analytical expressions for short-circuit and dark current densities are derived for a polycrystalline N+/P junction solar cell. A new solution of the continuity equation for the minority carrier which is adaptable with the boundary conditions when the cell is either illuminated or in the obscurity is given. For the first time, a three-dimensional model is developed for a polysilicon solar cell with multi-cylindrical grains. For an elementary solar cell, the results show that the three types of recombination such as the bulk recombination, the surface recombination and the recombination at the grain boundaries have an important effect on the cell parameters; and in some cases, one of these forms of recombination dominates the others. In the case of multi-cylindrical grains, the results of our approach show a decrease of the photovoltaic parameters according to the grain number especially for a thick solar cell. In addition, the comparison between an elementary cylindrical grain solar cell and an elementary cubic grain one shows an enhancement of the photovoltaic parameters for the cylindrical model.