An electroluminescent device includes: first to third pixel regions; a first electrode in each of the first to third pixel regions, wherein the first electrode of the third pixel region has a first thickness, the first electrode of the first pixel region has a second thickness less than the first thickness, and the first electrode of the second pixel region has a third thickness less than the second thickness; a second electrode in each of the first to third pixel regions; at least two electroluminescent units in each of the first and third pixel regions and disposed between the first electrode and second electrode, wherein one of the at least two electroluminescent units includes a blue light emitting layer and the other of the at least two electroluminescent units include a red/green light emitting layer; and a charge generation layer disposed between the at least two electroluminescent units.