Simultaneous Reduction of Silver and Indium in Silicon Heterojunction Solar Cells via Contact Transport Engineering

ABSTRACT Silver (Ag) and indium (In) represent the two major material cost drivers in silicon heterojunction (SHJ) solar cells, yet their reduction strategies are typically developed independently. Whether Ag‐lean metallization remains compatible with In‐lean transparent conductive oxides (TCOs) is still unclear. This work presents a systematic study integrating screen‐printed Ag‐lean pastes, including silver‐coated copper (Cu@Ag) and silver‐coated nickel (Ni@Ag), with three TCO configurations: indium tin oxide (ITO), an ITO/tin oxide (SnO X ) bilayer, and SnO X . The compatibility between Ag‐lean metallization and In‐lean TCOs is governed by the interplay between metallization properties and TCO‐dependent transport characteristics. The contact transport behavior of Ag‐lean metallization exhibits strong dependence on the carrier concentration of the underlying TCO. As carrier concentration decreases, thermally activated transport becomes increasingly important, consistent with the increased contact losses observed for lower‐carrier‐density TCOs. Combined with Cu@Ag paste, the ITO/SnO X bilayer achieves 25.62% efficiency with material cost reduction exceeding 65% relative to a conventional Ag‐ITO reference. Ni@Ag paste is demonstrated in high‐efficiency SHJ solar cells, achieving 25.02%. Device simulations further identify pathways for improving efficiency and reducing material consumption. These results provide a practical pathway toward combining Ag‐lean metallization with In‐lean TCO architectures in high‐efficiency SHJ solar cells.