Since Tang and Van Slyke have developed electroluminescent(EL) device driven at a low voltage consisting of an emitting layer and a hole transporting layer(about 50 nm), The organic ELD have been investgated by many researchers for applications in flat full-color displays. In this study, we fabricated successfully ell of three type as follow ITO/TPD/Znq₂/Al, We also report the enhancement of the efficiency in an organic ELD utilizing 8-hydroxyquinoline Zinc(Znq₂) and Tri-Phenylene Diamine(TPD) and it''s structural effect with their lifetime.