Organic electroluminescent device

1. An organic electroluminescent device comprising:

an anode;

an emission layer;

an anode-side hole transport layer between the anode and the emission layer and directly adjacent to the anode, the anode-side hole transport layer comprising an anode-side hole transport material and an electron accepting material doped in the anode-side hole transport material;

a middle hole transport layer between the anode-side hole transport layer and the emission layer, the middle hole transport layer consisting of a middle hole transport material; and

an emission layer-side hole transport layer between the middle hole transport layer and the emission layer, the emission layer-side hole transport layer being directly adjacent to the emission layer,

wherein the middle hole transport layer is directly between the anode-side hole transport layer and the emission layer-side hole transport layer,

the emission layer-side hole transport layer consists of an emission layer-side hole transport material represented by at least one selected from Compounds 1-1 to 1-28,

the middle hole transport material is at least one selected from Compounds 2-1 to 2-17, and

the emission layer-side hole transport material is different from the middle hole transport material:

2. The organic electroluminescent device of claim 1 , wherein the electron accepting material has a lowest unoccupied molecular orbital (LUMO) energy level at about −9.0 eV to about −4.0 eV.

3. The organic electroluminescent device of claim 1 , wherein the electron accepting material is at least one selected from Compounds 4-1 to 4-14:

wherein R is selected from hydrogen, deuterium, a halogen atom, an alkyl fluoride having 1 to 50 carbon atoms, a cyano group, an alkoxy group having 1 to 50 carbon atoms, an alkyl group having 1 to 50 carbon atoms, an aryl group having 6 to 50 carbon atoms for forming a ring, and a heteroaryl group having 5 to 50 carbon atoms for forming a ring,

X is one selected from the substituents represented by Formulae X1 to X7:

Y is selected from a methine group (—CH═) and nitrogen (—N═),

Z is selected from a pseudohalogen and sulfur,

Ar is selected from a substituted aryl group with an electron withdrawing group, an unsubstituted aryl group having 6 to 50 carbon atoms for forming a ring, and a substituted or unsubstituted heteroaryl group having 5 to 50 carbon atoms for forming a ring,

n is an integer selected from 0 to 10, and

in Formulae X1 to X7, Ra is selected from hydrogen, deuterium, a halogen atom, an alkyl fluoride having 1 to 50 carbon atoms, a cyano group, an alkoxy group having 1 to 50 carbon atoms, an alkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted aryl group having 6 to 50 carbon atoms for forming a ring, and a substituted or unsubstituted heteroaryl group having 5 to 50 carbon atoms for forming a ring.

4. The organic electroluminescent device of claim 1 , wherein the anode-side hole transport material is at least one selected from Compounds 2-1 to 2-17:

5. The organic electroluminescent device of claim 1 , wherein the emission layer comprises a compound represented by Formula 3:

wherein each Ar 1 is independently selected from hydrogen, deuterium, a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 50 carbon atoms for forming a ring, a substituted or unsubstituted alkoxy group having 1 to 50 carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 50 carbon atoms, a substituted or unsubstituted aryloxy group having 6 to 50 carbon atoms for forming a ring, a substituted or unsubstituted arylthio group having 6 to 50 carbon atoms for forming a ring, a substituted or unsubstituted alkoxycarbonyl group having 2 to 50 carbon atoms, a substituted or unsubstituted aryl group having 6 to 50 carbon atoms for forming a ring, a substituted or unsubstituted heteroaryl group having 5 to 50 carbon atoms for forming a ring, a substituted or unsubstituted silyl group, a carboxyl group, a halogen atom, a cyano group, a nitro group, and a hydroxyl group, and

n is an integer selected from 1 to 10.