An intermediate layer 220 may include a low-molecular-weight material or a high-molecular-weight material. When the intermediate layer 220 includes a low-molecular-weight material, the intermediate layer 220 may have a stacked structure of a hole injection layer (HIL), a hole transport layer (HTL), an emission layer (EML), an electron transport layer (ETL), and/or an electron injection layer (EIL), and may include any of various organic materials such as copper phthalocyanine (CuPc), N,N′-di(naphthalene-1-yl)-N,N′-diphenyl-benzidine (NPB), or tris-8-hydroxyquinoline aluminum (Alq3). Such layers may be formed by using vacuum deposition.

When the intermediate layer 220 includes a high-molecular-weight material, the intermediate layer 220 may have a structure including an HTL and an EML. In this case, the HTL may include poly(3,4-ethylenedioxythiophene) (PEDOT), and the EML may include a high-molecular-weight material such as a poly-phenylenevinylene (PPV)-based material or a polyfluorene-based material. The intermediate layer 220 may have any of various other structures. For example, at least one of layers constituting the intermediate layer 220 may be integrally formed over a plurality of the pixel electrodes 210. In some implementations, the intermediate layer 220 may include a layer that is patterned to correspond to each of the plurality of pixel electrodes 210.

The common electrode 230 may be located over the display area DA to cover the display area DA. The common electrode 230 may be integrally formed to cover a plurality of pixels.

A filler may be located between the common electrode 230 and the upper substrate 300. The filler may include, for example, at least one of a photocurable epoxy-based material and an acrylate-based material.