Separation of solar cell current into its constituent parallel currents under illumination

A method is presented which suggests the sharing out of total cell short circuit current among the constituent parallel branches of the equivalent circuit, allowing for the identification of their contributions to the total current–voltage (I–V) characteristics under illumination in solar cells described through two parallel diodes. The method is based on the fact that all parallel branches are always under the same voltage; in particular, the open circuit voltage is the same for the cell as a whole as well as for each of the two diodes. With the help of the parameters of each diode and its share in the cell short circuit current, its light I–V characteristic can be drawn, and its individual fill factor calculated. Furthermore, the method suggests a way to estimate the cell fill factor with the help of the individual fill factors. The application of the method is carried out on experimental data of a ZnO/CdS/CuGaSe2 single crystal solar cell.