Inkjet-printing　is　a　desirable　technology　for　organic　light　emitting　diodes　(OLEDs)　owing　to　its　compatibility　with　large-area　low-cost　full-color　pixelated　displays.　In　this　work,　we　proposed　a　strategy　to　fabricate　highly　efficient　inkjet-printed　blue　OLEDs　by　introducing　3,5-bis(N-car-bazolyl)benzene　(mCP)　as　the　host　material　into　organic　light　emitting　layers.　By　carefully　tailoring　the　weight　ratio　of　mCP　to　poly[(9,9-dioctyl-2,7-fluorene)-co-(dibenzothiophene-S,S-dioxide)]　(PFSO),　the　device　demonstrated　superior　charge　transport　capability,　leading　to　balanced　charge　transport　and　optimized　efficiency.　Furthermore,　in　combination　with　modifying　the　mCP:　PFSO　ink　formulation,　a　low-roughness　organic　emissive　film　on　Poly(ethylenedioxythiophene):polystyrenesulfonate　(PEDOT:PSS)　layer　was　achieved.　The　performance　of　the　inkjet-printed　device　has　been　significantly　improved　with　nearly　five　times,　which　exhibits　a　maximum　luminance　and　an　external　quantum　efficiency　of　3743　cd/m2　and　5.03%,　respectively.　The　icing　on　the　cake　is　that　we　fabricated　a　3-inch　blue　OLED　array　device　successfully　with　a　brightness　uniformity　of　92.7%,　which　shows　promising　potential　in　realizing　simple　structure　large-area　and　high-efficient　OLEDs　by　inkjet　printing.　©　2020　Elsevier　B.V.