Utilizing MoO_x-Au-MoO_x trilayers as transparent top electrodes in 2-terminal monolithic Si/perovskite tandem solar cells

Commercializing Si/perovskite tandem solar cells requires high-performing and cost-effective materials. The reliance on high-cost indium-based transparent conductive oxides (TCOs) for top electrodes poses a challenge for large-scale production. This necessitates the development of more cost-effective alternatives. This study investigates MoO_x-Au-MoO_x dielectric-metal-dielectric (DMD) trilayers as top transparent electrodes for 2-terminal monolithic Si/perovskite tandem solar cells. The DMD trilayers exhibited optoelectrical characteristics comparable to established TCO layers. When the thickness of the top MoO_x layer was adjusted to 30, 40, and 50 nm, the average light transmittance between 400 and 1100 nm was 70.6%, 71.1%, and 69.7%, respectively. Corresponding average power conversion efficiencies (PCEs) of the Si/perovskite tandem solar cells were 12.46%, 14.10%, and 15.97%, respectively. The observed increase in PCE with the thicker MoO_x layer was attributed to increased current density, resulting from enhanced light absorption by the Si subcell in the near-infrared region. The figure of merit (FOM) of the DMD trilayers ranged from 1.45 × 10^{− 3} to 1.75 × 10^{− 3} □/Ω. Photostability investigations performed on single-junction perovskite solar cells revealed that DMD trilayers improve the stability of devices in comparison to the conventional opaque gold electrodes. These findings indicate that MoO_x-Au-MoO_x DMD trilayers are a promising alternative to TCO layers for the top transparent electrodes in Si/perovskite tandem solar cells.