Non-radiative recombination loss at the hole transport layer (HTL)/perovskite interface in the narrow-bandgap (NBG) subcell constrains the power-conversion efficiency (PCE) of all-perovskite tandem solar cells 1,2. Minimizing charge recombination at the buried interface of lead-tin (Pb-Sn) based NBG perovskite solar cells have proven particularly challenging, as conventional long-chain amine-based passivation strategies often induce carrier transport losses, thereby limiting both the fill factors (FF) and short-circuit current density (Jsc) 35. Here,