The present invention relates to an organic electroluminescent device
comprising a gradual organic electroluminescent layer AxByCz inserted
between an anode electrode (may include a hole injection layer) and a
cathode electrode, wherein A, B, and C are mediums capable of transporting
holes, transporting electrons and injecting electrons respectively, and x,
y, and z denote the content of medium A, B, and C respectively. The
gradual layer with different materials combined is a mixed continuous
organic medium without heterojunctions, wherein the sum of x, y, and z is
100%. Moreover, x has a maximum, value adjacent to the anode electrode,
and the sum of y and z has a maximum value adjacent to the cathode
electrode, while the medium C is an electron injection component
comprising either a low work function metal, metal compound, metal alloy,
or an organic material with high electron affinity.
