Perovskite　solar　cells　(PSCs)　are　promising　photovoltaic　candidates　owing　to　their　high　efficiency　and　low-cost　fabrication.　However,　their　performance　is　significantly　limited　by　defects　at　grain　boundaries　and　surfaces,　which　induce　non-radiative　recombination　and　accelerate　degradation.　In　this　study,　4-fluorophthalic　anhydride　(4-FA)　additive　was　applied　to　selectively　anchor　and　passivate　defects　in　PSCs　for　the　first　time.　The　result　showed　that　the　uncoordinated　Pb2+　was　coordinated　by　a　lone　pair　of　electrons　in　the　carbonyl　group　through　Lewis　acid–base　interaction.　Additionally,　the　hydrogen　bonds　were　formed　between　F　atoms　in　4-FA　and　–NH2　in　FAI,　improving　the　crystal　quality.　Moreover,　the　hydrophobic　nature　of　F　atoms　enhanced　the　environmental　stability　of　PSCs.　As　a　result,　the　4-FA-modified　perovskite　film　exhibited　a　reduced　defect　density　and　a　longer　carrier　lifetime.　In　addition,　the　power　conversion　efficiency　of　the　film　increased　from　21.37　%　to　24.10　%,　retaining　87　%　of　its　initial　value　after　60　days　in　unencapsulated　ambient　air.　©　2025　Elsevier　Inc.