An OLED device comprising an anode and a cathode spaced from the anode,
two EL units disposed between the anode and cathode, such EL units being
in contact with each other and each having at least one light emitting
layer; and each EL unit further includes a p-type doped organic hole
transporting layer disposed between the light emitting layer and the
anode, and an n-type doped organic electron transporting layer disposed
between the light emitting layer and the cathode.