A model is developed to explain the current-voltage (J-V) characteristics of polycrystalline CdTe-CdS solar cells with different grain sizes of CdTe. Analytical expressions are derived for J-V characteristics by solving the continuity equation for electron and holes using appropriate boundary conditions. The grain size (g) effect is taken into account via the parameters like mobility, diffusion length and life-time of carriers. The model developed is fitted with the experimental data and it shows a good agreement.
