This work presents a 3D modelling study of the effect of grain size on the electrical parameters such as maximum electric power, fill factor and conversion efficiency, of a polycrystalline silicon solar cell.
To study effects of grains size on the performance of the polycrystalline silicon solar, we used in our model variables silicon grain sizes. Taking into account the variation of grain size led to the analytical expressions of carrier density, photocurrent, photovoltage and electric power which are function of grain size. In this study, the solar cell was illuminated with an intense light. Then the high photogeneration of carrier in the base of the solar cell in this kind of illumination allows us to take into account the carrier gradient electric field in the base of the solar cell.
We studied effects of grain sizes on the J-V characteristics of the solar cell and we calculated the short circuit current density and the open circuit voltage according to the grain size. We also studied the effect of grain size on the P-V characteristics and we determine the values of maximum electric power Pmax and the solar cell conversion efficiency according to grain size. Knowing the short circuit current density, the open circuit voltage and the maximum electric power which depend on the grain size variation, we studied also the effect of grain size on the fill factor of the solar cell.
The results of this study have showed that the maximum electric power, the fill factor and the conversion
efficiency of the solar cell increase with the increase of the grain size of polycrystalline silicon cell.

Conversion efficiency, fill factor, grain size, intense light, maximum electric power, polycrystalline solar cell