Self-assembled molecules with hydrogen-bond networks enable efficient all-perovskite tandem solar cells

Hole-selective self-assembled monolayers have advanced the performance of perovskite solar cells (PSCs), yet their excessive intermolecular interactions result in undesirable self-aggregation and weak interfacial contact. Here we devise a bicarbazole-based dimeric structure incorporating amide units as dual hydrogen-bond donors and acceptors to enable the formation of hydrogen-bonding networks within the molecules and with transparent conductive oxide. This design promotes homogeneous molecular arrangement and well-aligned energy levels, minimizing hole-transport loss and enhancing interfacial stability. We achieve an efficiency of 21.56% in a 1.77 eV PSC, with an open-circuit voltage of 1.35 V and a fill factor of 85.76%. This strategy is also applicable to 1.56 eV PSCs, affording efficiencies of 26.80% (certified 26.57% by current density–voltage ( J – V ) scan and 25.92% steady-state measured over 300 s). Most notably, the integrated all-perovskite tandem solar cell yields an efficiency of 30.19% (certified 29.38% by J – V scan and 28.40% steady state measured over 120 s).