Organic light-emitting device

An organic light-emitting device comprising:

• a positive electrode;
• a negative electrode;
• and
• at least one organic material layer between the positive electrode and the negative electrode, wherein
• the at least one organic material layer comprises a hole-injecting layer, a hole-transporting layer, an emission layer comprising a host material and a dopant material, an electron-transporting layer, an electron-injecting layer, and
• a lifetime enhancement layer between the emission layer and the electron-transporting layer, the lifetime enhancement layer comprising a bipolar compound comprising an electron withdrawing group (EWG) and an electron donating group (EDG), the bipolar compound having an ionization potential of 5.5 eV or greater, a difference between an energy of the highest occupied molecular orbital and an energy of the lowest occupied molecular orbital of greater than 3.0 eV, a triplet energy of 2.3 eV or greater, and a difference between a singlet energy and the triplet energy of less than 0.5 eV,
• wherein the bipolar compound is a compound represented by Formula 1:
• where
• X1 is selected from the group consisting of O, S, Se, N(Ar1), C(Ar2)(Ar3), and Si(Ar4)(Ar5),
• Y1 to Y4 are each independently N or C(R1), wherein a plurality of R1s are the same or different and one or more R1s optionally bind to a nearby group to form a condensed ring;
• and
• X2 and X3 are each independently N or C (R2), wherein a plurality of R2s are the same or different and one or more R2s optionally bind to a nearby group to form a condensed ring;
• R1 to R2, and Ar1 to Ar5 are each independently selected from the group consisting of a hydrogen, a deuterium, a halogen group, a cyano group, a nitro group, an amino group, a C1˜C40 alkyl group, a C2˜C40 alkenyl group, a C2˜C40 alkynyl group, a C3˜C40 cycloalkyl group, a heterocycloalkyl group having 3 to 40 ring atoms, a C6˜C60 aryl group, a heteroaryl group having 5 to 60 ring atoms, a C1˜C40 alkoxy group, a C6˜C60 aryloxy group, a C1˜C40 alkylsilyl group, a C6˜C60 arylsilyl group, a C1˜C40 alkylboron group, a C6˜C60 arylboron group, a C1˜C40 phosphine group, a C1˜C40 phosphine oxide group, and a C6˜C60 arylamine group, and
• a C1˜C40 alkyl group, a C2˜C40 alkenyl group, a C2˜C40 alkynyl group, a C3˜C40 cycloalkyl group, a heterocycloalkyl group having 3 to 40 ring atoms, a C6˜C60 aryl group, a heteroaryl group having 5 to 60 ring atoms, a C1˜C40 alkoxy group, a C6˜C60 aryloxy group, a C1˜C40 alkysilyl group, a C6˜C60 arylsilyl group, a C1˜C40 alkylboron group, a C6˜C60 arylboron group, a C1˜C40 phosphine group, a C1˜C40 phosphine oxide group, and a C6˜C60 arylamine group each independently substituted with at least one selected from the group consisting of a deuterium, a halogen group, a cyano group, a nitro group, an amino group, a C1˜C40 alkyl group, a C2˜C40 alkenyl group, a C2˜C40 alkynyl group, a C3˜C40 cycloalkyl group, a heterocycloalkyl group having 3 to 40 ring atoms, a C6˜C40 aryl group, a heteroaryl group having 5 to 40 ring atoms, a C1˜C40 alkoxy group, a C6˜C60 aryloxy group, a C1˜C40 alkylsilyl group, a C6˜C60 arylsilyl group, a C1˜C40 alkylboron group, a C6˜C60 arylboron group, a C1˜C40 phosphine group, a C1˜C40 phosphine oxide group, and a C6˜C60 arylamine group.