Modeling of three-terminal heterojunction bipolar transistor solar cells

Three-terminal solar cells exploiting the heterojunction bipolar transistor structure combine the advantages of independently connected tandem cell architectures - suboptimal gaps, high resilience to spectral variations and to radiation damage - to a simple monolithic structure, since they do not need tunnel junctions. In this work, we study this novel device concept by means of optoelectronic simulations based on realistic material parameters, and discuss the solar cell operation and its design optimization.