Quantum　dots　(QDs)　with　an　alloy　shell　(CdSe@ZnS/ZnS)　are　one　of　the　most　promising　emitters　for　opto-electronic　devices　for　their　superior　properties　such　as　narrow　full　width　at　half　maximum　(FWHM),　high　color　purity　and　tunable　wavelength.　However,　the　presence　of　lattice　stresses　during　the　internal　growth　of　quantum　dots　can　cause　severe　exciton　bursts.　Optimizing　the　ramp-up　process　during　the　core　growth　of　quantum　dots　and　rising　the　temperature　when　cladding　with　ZnS　shells　is　an　effective　strategy　for　obtaining　high-quality　quantum　dots.　Besides,　the　stability　of　quantum　dots　is　further　modified　by　using　1-Octanethiol　(OT)　as　li-gands.　Detailed　analyses　of　the　morphology,　colloidal　stability,　and　luminescence　performance　of　QDs　were　represented.　Finally,　green　CdSe@ZnS/ZnS　QLEDs　with　prolonged　carrier　lifetimes　and　less　defect　state　densities　achieved　peak　luminescence　at　361850　cd/m2　with　a　current　efficiency　(CE)　of　33　cd/A.　This　work　provides　a　better　understanding　of　the　relationship　between　defect　state　density　and　the　performance　of　quantum　dots　for　designing　and　fabricating　high-performance　light-emitting　diodes.