Embodiments of the present disclosure generally relate to electroluminescent devices, such as organic light-emitting diodes, and displays including electroluminescent devices. In an embodiment is provided an electroluminescent device that includes a pixel defining layer, an organic emitting unit disposed over at least a portion of the pixel defining iayer, and a filler layer disposed over at least a portion of the organic emitting unit, wherein a refractive index of the pixel defining iayer is iower than a refractive index of the filler Iayer, and wherein the refractive index of the pixel defining Iayer is Iower than a refractive index of one or more layers of the organic emitting unit, in another embodiment is provided a display device that includes a substrate, a thin film transistor formed on the substrate, an interconnection electrically coupled to the thin film transistor, and an electroluminescent device electrically coupled to the interconnection.