A white organic light-emitting diode includes two symmetric emission
layers and a middle emission layer. The two symmetric emission layers
emit a first color light with approximately the same frequency
components. The middle emission layer is located between the two
symmetric emission layers. The middle emission layer emits a second color
light with frequency components different from main frequency components
of the first color light. When the voltage applied to the organic
light-emitting diode changes and leads to a decrease of luminescent
intensity of one of the symmetric emission layers, the other symmetric
emission layer automatically increases the luminescent intensity to
compensate for the reduced light intensity.