Researchers led by Fraunhofer ISE have demonstrated zinc-doped tin oxide (ZTO) as a promising indium-free alternative to indium tin oxide (ITO) for recombination layers in fully textured perovskite-silicon tandem solar cells. ZTO offers comparable device efficiencies of 27-28% under current-matching conditions, providing a scalable, indium-free pathway for high-performance tandem photovoltaics without efficiency loss. The study compared ZTO, aluminum-doped zinc oxide (AZO), and ITO transparent conductive oxides, with ZTO showing superior compatibility with hybrid-processed perovskite top cells on TOPCon-based perovskite-silicon tandem solar cells. The research emphasizes the importance of processing parameters such as sputter parameters and annealing in tuning the structural and electrical properties of the transparent conductive oxides.