Breaking the 35% Efficiency Milestone: Material Innovations and Interface Mechanisms in Monolithic Perovskite/Silicon Tandem Solar Cells

Crystalline silicon solar cells are approaching their theoretical Auger efficiency limit, necessitating tandem architectures that transcend the Shockley–Queisser constraint and lower the cost of electricity. Monolithic perovskite/silicon tandem solar cells (PSTSCs) have breached the 35% power conversion efficiency barrier, emerging as the leading candidate to disrupt the photovoltaic landscape. However, translating this laboratory success to terawatt‐scale deployment requires precise control over charge transport and interfacial recombination at the interconnecting layer (ICL). This review examines the material innovations driving this evolution, grounded in a quantitative loss‐budget analysis, with a focus on the ICL and full‐dimensional interface engineering. We first examine the evolving ICL paradigm, from defect‐mediated transport in amorphous silicon to efficient band‐to‐band tunneling in polycrystalline silicon junctions, and the enhanced charge extraction enabled by transparent conductive oxides with self‐assembled monolayers (SAMs), whose Ohmic contact formation we trace through an anchoring‐to‐Fermi‐level‐depinning mechanism. We further dissect breakthroughs mitigating non‐radiative losses on textured silicon substrates, where SAMs and passivation strategies overcome steric hindrance and contact resistance, and where the same pyramid texture governs wide‐bandgap perovskite crystallization and its process‐engineering trade‐offs. Finally, we navigate the “efficiency‐stability‐cost” trilemma, addressing halide‐segregation and ion‐migration suppression under a standardized stability framework, alongside scalable manufacturing toward industrial translation.