In order to make full use of energy transferring and hole blocking between the subject and the object in the light-emitting layer,the high efficiency blue light device is fabricated,whose structure is ITO/m-MTDATA(25 nm)/NPB(15 nm)/Ir(ppz)3(10 nm)/Simcp:Firpic(30 nm,6%)/HBL(35 nm)/ LiF(1 nm)/Al(200 nm).We have studied the effect of three different hole blocking layers on the current efficiency of blue light devices.The results has demonstrated that the material BCP,whose HOMO level is lower,has ...