SPICE modeling of cascade solar cells

An equivalent circuit representing a two-junction cascade solar cell is presented. The solar cell diode equations are applied. Terms for the light-generated currents, diffusion currents, space charge recombination currents, series and shunt resistance, the resistance for the window layer and the substrate, and the equivalent resistance for the tunnel diode are included. An AlGaAs/GaAs cascade solar cell is considered as an example. SPICE was used to simulate the cascade solar cell for the following: the cascade solar cell I-V curve with temperature as a parameter, the cascade cell P-V curves with temperature as a parameter, open-circuit voltage of the cascade cell versus temperature, and fill factor of the cascade cell versus temperature. The results of this SPICE simulation compared favorably with the data available in the published literature