Impact of loading topology and current mismatch on current-voltage curves of three-terminal tandem solar cells with interdigitated back contacts

The electrical output characteristics of a three-terminal tandem solar cell with top and interdigitated back contacts were experimentally investigated under different external loading and current mismatch conditions. Regardless of the chosen loading topology (i.e., which terminal is common), the output power for the two sub-circuits of the three-terminal tandem added up to the same value. However, the current-voltage curve of one subcircuit depended on the loading topology and biasing condition of the other sub-circuit, which can be explained by a simple equivalent circuit model. A negative current was observed for two topologies depending on the current mismatch between the top and bottom cells, which suggests power injection into one of the sub-circuits. This negative current did not appear for a third topology. These results indicate that the third topology is a useful way to maximise the power, especially under spectrum-varying conditions.

Automated summary

The electrical output characteristics of a three-terminal tandem solar cell were experimentally investigated under different external loading and current mismatch conditions. The results showed that the output power for the two sub-circuits of the three-terminal tandem always added up to the same value, regardless of the chosen loading topology. However, the current-voltage curve of one subcircuit depended on the loading topology and biasing condition of the other sub-circuit.