An efficient organic light emitting diode (OLED) device--incorporating a
stack of thin films comprising a cathode, electron transport layer, hole
modulating conductive layer, host layer, electron modulating conductive
layer, hole transport layer, hole injection layer and a transparent anode
layer--has increased recombination efficiency to generate substantial
amount of light. The electron modulating electrode and hole modulating
electrode embedded in the stack are applied with appropriate electrical
bias to contain the electrons and holes respectively inside the host
layer to enhance recombination and consequently light output.