IntroductionSince Tang[1] firstly reported the electrolu-minescence of 8- hydroxyquinoline aluminium,much attention has been paid to the organic com-pound as electro- luminescent material.Especially,electron transport materials play an important rolein or IntroductionSince Tang [1] initially reported the electrolu-minescence of 8-hydroxyquinoline aluminum, much attention has been paid to the organic com-pound as electro- luminescent material. Especially in electron transport materials play an important role in or