Effects of shunt and series resistances on the performance of a tandem solar cell

This paper investigates the effects of the shunt and series resistances on the performance of a tandem solar cell. There are five output parameters considered as performance indicators of a solar cell: the short-circuit current, the open circuit voltage, the power at the maximum point, the efficiency and the output energy. The performance indicator used in this study is the short-circuit current of the tandem cell as it is directly influenced by the incident irradiance and the power at the maximum point. To observe the changes in the short-circuit current of a tandem solar cell, the shunt resistance of each cell in a tandem solar cell was varied, i.e. in a range of 0Ω to 10kΩ for the top cell and from 0Ω to 12kΩ for the bottom cell. The series resistances of the cell were also changes from 0Ω to 1Ω for the top cell and from 0Ω to 2Ω for the bottom cell. Results of the simulation confirm that while the short-circuit current of such a tandem device is strongly influenced by the lowest current of its sub-cells, a reduction in the shunt resistance of the bottom cell has a positive impact on the overall short-circuit current of device, which increases by almost 9% for the device simulated. Variations in the series resistances have almost no influence on the short circuit of the tandem solar cell.