Evaluation of the InGaP, GaAs, and Si-nanowire Multijunction Four-terminal Bifacial Solar Cell

Abstract

Multijunction bifacial solar cells combine multiple cells to simultaneously generate power from both the front and rear sides. The architecture significantly enhances total energy yield and conversion efficiency beyond the theoretical limit of single-junction cells, making the architecture an up-and-coming option for applications where both high performance and spatial light utilization are critical. The study investigated bifacial solar cell combinations using three single-junction cells (GaAs, InGaP thin-film, and Si-nanowire (SiNW) heterojunction) under reflected light from concrete, dry grass, and black sand. For the double-junction cell, GaAs is the preferred top cell, with SiNW favored as the bottom cell for dry grass and black sand, and GaAs for concrete. The triple-junction cell uses an InGaP//GaAs tandem as the top cell, maintaining the same bottom cell preferences. Ultimately, selecting between the double and triple junction designs depends on balancing the efficiency improvement against the increased fabrication cost, providing insight into optimal photovoltaic combinations for commercial bifacial solar cells.