Efficiency Enhancement of Perovskite Solar Cells Using Heterojunction Bipolar Transistor Configuration

Recently, perovskites have shown immense potential as solar cell active layer materials, achieving photo-conversion efficiency over 20%. In the future, a novel device architecture has the ability to further stimulate the device performance. In this article, we propose a three-terminal heterojunction bipolar transistor (HBT) architecture to enhance the photo-conversion efficiency of perovskite solar cells. We performed an optoelectronic simulation to characterize the proposed heterojunction bipolar transistor solar cell and analyze its performance metrics by varying different design parameters. In doing so, we vary the thickness of active layers in the structure and change the doping concentration of three regions to maximize the device efficiency. We estimate an absolute improvement in efficiency of 10.84% compared to the current record efficiency of single-junction perovskite solar cells (34.54% versus 23.7%), for a 400 nm/450 nm perovskite/perovskite heterostructure. The analyses and results presented in this article would provide a promising direction to the design of solar cell architecture utilizing HBT configuration.