Hybrid Sn–Pb perovskite solar cells are promising candidates for tandem photovoltaic applications; however, their performance is frequently limited by severe photovoltage loss and insufficient operational stability, which mainly originate from interfacial recombination and poorly controlled crystallization processes. In this talk, I will present our systematic strategies to regulate interfacial recombination, crystallization dynamics, and carrier-selective contact properties through targeted interface engineering, growth modulation, and hole-transport-layer-free design. Specifically, dedoping PEDOT:PSS effectively reduces interfacial energy mismatch and suppresses non-radiative recombination, enabling more efficient hole extraction and a marked enhancement in open-circuit voltage.[1] Further modification using cPTANMe as a tailored hole transport layer improves interfacial energetics and charge selectivity, thereby minimizing recombination losses at the perovskite/HTL interface.[2] In parallel, a fullerene derivative is introduced as an additive to modulate crystallization behavior, refine film morphology, and stabilize the perovskite lattice, which mitigates interfacial degradation and enhances device durability. Beyond conventional HTL-based architectures, I will also discuss our recent progress in HTL-free hybrid Sn–Pb perovskite solar cells, where careful control of buried-interface quality, crystallization pathways, and interfacial energetics enables efficient charge extraction even in the absence of a dedicated hole transport layer. These HTL-free devices provide a simplified platform to uncover the intrinsic interplay between ionic distribution, interfacial defects, and non-radiative recombination, while also offering a practical route toward reducing parasitic losses and fabrication complexity. Overall, the synergistic control of charge-selective interfaces, crystal growth pathways, and contact architecture leads to simultaneous improvements in photovoltage and operational stability, while also providing fundamental insight into the voltage–stability trade-off in hybrid Sn–Pb perovskite systems. These findings establish practical design principles for engineering high-performance and durable narrow-bandgap absorbers, paving the way toward more efficient and reliable next-generation tandem photovoltaic technologies.