Perovskite　quantum　dots　(PQDs)　have　emerged　as　promising　candidates　for　next-generation　high-quality　lighting　and　high-definition　displays　due　to　their　outstanding　luminescence　properties,　characterized　by　a　narrow　emission　spectrum　and　tunable　color.　However,　during　the　purification　process　involving　polar　solvents,　ligand　detachment　from　the　quantum　dot　surface　often　induces　crystal　defects,　thereby　compromising　their　long-term　stability.　Herein,　the　effects　of　various　post-processing　strategies　on　PQD　performance　are　systematically　explored,　including　the　use　of　oleic　acid　(OA),　didodecyldimethylammonium　bromide　(DDAB),　and　their　combinations,　alongside　OA-assisted　synthesis.　Furthermore,　a　synergistic　post-processing　strategy　based　on　DDAB-NaMeS　(sodium　methanesulfonate)　is　proposed　to　elucidate　the　mechanism　of　ligand　reconstruction　on　the　quantum　dot　surface　during　purification.　The　resulting　PQDs　demonstrated　excellent　stability　over　a　storage　period　exceeding　one　month,　and　the　corresponding　Quantum　Dots　Light-Emitting　Diodes　(QLEDs)　achieved　a　peak　external　quantum　efficiency　(EQE)　of　9.82%,　representing　a　1.91-fold　improvement　over　standard　devices.　These　QLEDs　exhibited　exceptional　optoelectronic　performance,　underscoring　their　potential　for　application　in　other　sulfonic　acid　ligands　and　perovskite-based　materials.　©　2025　Wiley-VCH　GmbH.