Perovskite　light-emitting　diodes　(PeLEDs)　have　attracted　wide　attention　due　to　their　excellent　photoelectric　properties.　A　variety　of　additives　have　been　studied　for　perovskite　emission　layers　to　enhance　the　performance　of　PeLEDs.　However,　the　buried　interface,　which　also　has　significant　influence　on　the　crystallization　kinetics　and　exciton　recombination　dynamics　of　the　perovskite　emission　layer,　remains　to　be　explored.　In　this　work,　we　introduced　a　new　ionic　liquid　1-Ethyl-3-methylimidazolium　dicyanamide　(EMIM　DCA)　with　the　characteristics　of　low　viscosity　and　high　conductivity　into　the　interfacial　layer　between　the　hole　transport　layer　(HTL)　and　the　perovskite　film.　Due　to　the　strong　interaction　between　the　EMIM　DCA　and　perovskite,　the　crystallization　of　the　perovskite　film　is　obviously　improved　and　the　defects　at　the　interface　are　well　passivated.　As　a　result,　the　nonradiative　recombination　in　the　interlayer　is　significantly　reduced.　In　addition,　the　introduction　of　EMIM　DCA　promoted　the　injection　of　charge　carriers,　thus　achieving　a　high　luminance　of　32310　cd　m(-2)　and　enabling　the　maximum　external　quantum　efficiency　(EQE)　of　the　PeLEDs　increased　from　10.2　%　to　18.7　%.