Interface parallel dipole regulation in all-perovskite tandem solar cells

The abstract should be a single paragraph that summarises the content of the article Constructing all-perovskite tandem solar cells (TSCs) provides an effective route to surpass the efficiency limit of single-junction devices. However, huge non-radiative recombination losses in wide-bandgap (WBG) subcells degrade their performance from theoretical predictions. Here, we propose a parallel dipole engineering strategy employing tailored phenoxyethylammonium halides (POEAX, X=I, Br, Cl) to simultaneously heal defects and modulate interfacial electric fileds. POEA+ forms parallel dipole moment at the perovskite/C60 interface, effectively binding with Pb2+ defects and enhancing the carrier transport. Synergistically, Cl- amplifies the dipole-bridged defect healing and optimizes the energy level alignment, leading to highly improved film homogeneity and suppressed recombination. These advantages lead to a power conversion efficiency (PCE) of 19.54% and a remarkable open-circuit voltage of 1.352 V in 1.77 eV WBG perovskite solar cells (PSCs). Furthermore, integrated with low-bandgap PSCs, all-perovskite TSCs with a champion PCE of 28.92% (certified 28.51%) and excellent stability are realized.