wherein the organic material layer comprises a light emitting layer, a hole transport layer formed between the light emitting layer and the first electrode, and an emission-auxiliary layer formed between the hole transport layer and the light emitting layer, and the hole transport layer and/or the emission-auxiliary layer comprises a compound of Formula 1:

wherein:

X is O or S,

R¹ to R³ are each independently selected from the group consisting of deuterium, a C₆-C₁₈ aryl group, a fluorenyl group, a C₂-C₁₈ heterocyclic group containing at least one heteroatom selected from the group consisting of O, N and S, a C₁-C₁₀ alkyl group, and at least one pair of neighboring groups of R¹, R² or R³ may be optionally linked each other to form a ring, with the proviso that R¹, R² and the ring optionally formed by a pair of neighboring groups of R¹ or R² exclude a substituted or unsubstituted dibenzothiophene, dibenzofuran, or fluorene ring,

m is an integer of 0 to 4, n and o are each an integer of 0 to 3, and a plurality of R¹, R² and R³ are each the same or different from each other when m, n and o are each an integer of 2 or more,

L¹ to L⁵ are each independently selected from the group consisting of a single bond, a C₆-C₁₈ arylene group, and a fluorenylene group,

Ar¹ to Ar⁴ are each independently selected from the group consisting of a C₆-C₁₈ aryl group, a C₅-C₁₈ heterocyclic group containing at least one heteroatom selected from the group consisting of O, N, and S, and a fluorenyl group, and at least one of Ar¹ to Ar⁴ is the formula 1a below,

in Formulas 1a,

Y is S, O, C(R^a)(R^b) or N(R^c), wherein R^a to R^c are each independently a C₆-C₁₈ aryl group, a fluorenyl group, a C₂-C₁₈ heterocyclic group containing at least one heteroatom selected from the group consisting of O, N, and S, a C₁C₁₀ alkyl group, wherein R^a and R^b may be optionally linked each other to form a spiro compound together with C bonded to them,

R⁴ and R⁵ are each independently selected from the group consisting of deuterium, a C₆-C₁₈ aryl group, a fluorenyl group, a C₂-C₁₈ heterocyclic group containing at least one heteroatom selected from the group consisting of O, N, and S, a C₁-C₁₀ alkyl group, neighboring groups of R⁴ and R⁵ may be optionally linked each other to form a ring, p is an integer of 0 to 4, q is an integer of 0 to 3, and a plurality of R⁴s and R⁵s are each the same or different from each other when p and q are each an integer of 2 or more,

when R¹ to R⁵ are each the aryl group, fluorenyl group, heterocyclic group, alkyl group, they may be each optionally further substituted with one or more substituents selected from the group consisting of deuterium, a C₁-C₁₀ alkyl group, a C₆-C₁₈ aryl group, a C₆-C₁₈ aryl group substituted with deuterium, a fluorenyl group, and a C₅-C₁₈ heterocyclic group containing at least one heteroatom selected from the group consisting of O, N, and S, and

when Ar¹ to Ar⁴ are each the aryl, fluorenyl, or heterocyclic group, they may be each optionally further substituted with one or more substituent(s) selected from the group consisting of deuterium, a C₁-C₁₀ alkyl group, a C₆-C₁₈ aryl group, a C₆-C₁₈ aryl group substituted with deuterium, a fluorenyl group, and a C₅-C₁₈ heterocyclic group containing at least one heteroatom selected from the group consisting of O, N, and S.