Homogenizing the Halogen Distribution via a Multifunctional Fluorine‐Containing Additive Toward High‐Performance Inverted Wide‐Bandgap Perovskite Solar Cells

Abstract Wide‐bandgap perovskite solar cells, which are essential for tandem photovoltaics, easily suffer from open‐circuit voltage (V_OC) losses due to challenges in suppressing halogen heterogeneity and defect‐related nonradiative recombination in the active layers. Herein, a multifunctional fluorine‐containing additive of 8‐pentafluorobenzyloxy quinoline (8‐PFBQ) is explored to modulate the crystallization and defect properties of wide‐bandgap (1.67 eV) perovskites, enhancing both efficiency and operational stability of ensuing solar cells. It is demonstrated that the quinoline group of 8‐PFBQ can strongly coordinate with the lead ions and the fluorinated benzyl group effectively interacts with the organic halides through anion‐π and hydrogen bonding interactions simultaneously. These synergistic effects improve crystal quality and composition homogeneity, holistically reducing defects in the perovskite active layers. The resulting wide‐bandgap solar cells achieve a champion power conversion efficiency of 22.22%, featuring a high V_OC of 1.243 V and a two‐fold enhancement in the operational stability. This work presents an alternative strategy for defect management in wide‐bandgap perovskites, offering insights for advancements in both single‐junction and tandem photovoltaics.