Perovskite-perovskite-silicon triple junction solar cells with improved carrier and photon management

Perovskite–silicon triple-junction photovoltaics offer efficiency gains beyond dual-junction devices, but at the expense of added complexity. Here, we address two main challenges in perovskite-silicon-based triple-junction solar cells: reduced open-circuit voltage in the wide-bandgap top-cell and limited current density in the middle-cell. Additive engineering with 4-hydroxybenzylamine modulates the crystallization dynamics of the top-cell absorber and suppresses bulk recombination, enabling open-circuit voltages up to 1.405 V. The three-step-manufactured lead-halide middle-cell absorbers result in an increasing thickness and a reduced bandgap, thereby boosting the current density. Low-refractive-index SiOx nanoparticles accumulated in the front valleys of the textured silicon bottom-cell act as a middle-reflector, enhancing light absorption in the middle-cell. These innovations are then combined in 1-cm2 perovskite-perovskite-silicon devices, reaching a steady-state efficiency of 30.5%.