GENERAL EXPRESSION FOR THE FILL FACTOR OF A REAL HOMOJUNCTION SOLAR-CELL USING A SINGLE EXPONENTIAL MODEL

An expression for the fill factor of a real homojunction solar cell having resistive and current leakage losses is derived using Lagrange's undetermined multiplier technique based on a single exponential model. The expression derived is quite general, but not completely analytic and is applicable to various types of solar cells, in particular, polycrystalline solar cells, where series and shunt resistances cannot be excluded. It is observed that for given values of series and/or shunt resistance, the fill factor is determined by reverse saturation current and diode quality factor of the solar cell.