Condensed cyclic compound and organic electroluminescence device including the same

An organic electroluminescence device, comprising:

• a first electrode;
• a hole transport region disposed on the first electrode;
• an emission layer disposed on the hole transport region;
• an electron transport region disposed on the emission layer;
• and
• a second electrode disposed on the electron transport region, wherein
• the electron transport region comprises a condensed cyclic compound represented by the following Formula 1:
• where X and Z are each independently a substituted or unsubstituted pentagonal hydrocarbon ring, a substituted or unsubstituted hexagonal hydrocarbon ring, a substituted or unsubstituted pentagonal heterocycle, or a substituted or unsubstituted hexagonal heterocycle,
• Y is a substituted or unsubstituted pentagonal heterocycle,
• the pentagonal heterocycle and the hexagonal heterocycle each independently includes one heteroatom,
• a and b are each independently 0 or 1,
• Y is not a pentagonal heterocycle with an N,
• a quinolinyl group or
• is bonded to X if Y is a pentagonal heterocycle with an oxygen atom or a sulfur atom, and
• Ar1 is an unsubstituted phenyl group.