Electron buffering materials, electron transport materials and organic electroluminescent device comprising the same

An electron buffering material comprising a compound represented by the following formula 1:

• wherein,
• X1 represents —N═, —O— or —S—;
• Y1 represents —N═, —NR8—, —O— or —S—;
• where X1 is —N═, Y1 is —NR8—, —O— or —S—;
• where X1 is —NR7—, Y1 is —N═, —O— or —S—;
• the case that both of X1 and Y1 are —O— or —S—, and the case that one of X1 and Y1 is —O—, and the other is —S— are excluded;
• R1 represents a substituted or unsubstituted (C6-C30)aryl, or a substituted or unsubstituted (3 to 30-membered)heteroaryl;
• R2 to R4, R7 and R8, each independently, represent hydrogen, deuterium, a halogen, a cyano, a substituted or unsubstituted (C1-C30)alkyl, a substituted or unsubstituted (C6-C30)aryl, a substituted or unsubstituted (3 to 30-membered)heteroaryl, a substituted or unsubstituted (C3-C30)cycloalkyl, a substituted or unsubstituted (C1-C30)alkoxy, a substituted or unsubstituted tri(C1-C30)alkylsilyl, a substituted or unsubstituted di(C1-C30)alkyl(C6-C30)arylsilyl, a substituted or unsubstituted (C1-C30)alkyldi(C6-C30)arylsilyl, a substituted or unsubstituted tri(C6-C30)arylsilyl, a substituted or unsubstituted mono- or di-(C1-C30)alkylamino, a substituted or unsubstituted mono- or di-(C6-C30)arylamino, or a substituted or unsubstituted (C1-C30)alkyl(C6-C30)arylamino, or may be linked to an adjacent substituent(s) to form a substituted or unsubstituted (C3-C30), mono- or polycyclic, alicyclic or aromatic ring, whose carbon atom(s) may be replaced with at least one heteroatom selected from nitrogen, oxygen, and sulfur;
• a represents an integer of 1;
• b and c, each independently, represent an integer of 1 or 2;
• d represents an integer of 1 to 4;
• and
• the heteroaryl contains at least one heteroatom selected from B, N, O, S, Si and P.