The present invention relates to compounds of the formula (1) which are suitable for use in electronic devices, in particular organic electroluminescent devices, and to organic electroluminescent devices which comprise these compounds.

An organic electroluminescence device includes: an anode; a cathode; and an emitting layer provided between the anode and the cathode, in which the emitting layer contains a delayed fluorescent compound M2 and a compound M3 represented by a formula (3) and a singlet energy S.sub.1(M2) of the compound M2 and a singlet energy S.sub.1(M3) of the compound M3 satisfy a relationship of a numerical formula (Numerical Formula 1) below, S.sub.1(M3)>S.sub.1(M2) . . . (Numerical Formula 1). In the formula (3), A3 is a group represented by a formula (3a) or the like.

##STR00001##

Disclosed is an organometallic compound represented by a following Chemical Formula 1. When the organometallic compound is used as dopant of a light-emitting layer of an organic electroluminescent device, rigidity is imparted to the organometallic compound molecule such that a full width at half maximum (FWHM) is narrow and thus color purity is improved. Further, a non-luminescent recombination process is reduced such that luminous efficiency and lifespan of the organic electroluminescent device are improved. Chemical Formula 1 is shown below:

##STR00001##

An organometallic compound represented by Formula 1 emits deep blue light. A light-emitting device including the organometallic compound, and an electronic apparatus including the light-emitting device may have excellent or suitable driving voltage, luminescence efficiency, color conversion efficiency, and/or lifespan characteristics:

##STR00001##

In Formula 1, X.sub.1 to X.sub.4 are each independently C or N, Y.sub.11 is C(Z.sub.11) or N, and Y.sub.12 is C(Z.sub.12) or N.

An organic electroluminescence device of an embodiment includes a first electrode, a second electrode facing the first electrode, and organic layers disposed between the first electrode and the second electrode, wherein the organic layers include at least one organic layer that includes a fused polycyclic compound represented by Formula 1, thereby showing improved emission efficiency.

##STR00001##

Disclosed are a heterocyclic compound represented by Formula 1 and an organic light emitting device using the same. The heterocyclic compound is used as a material for hole injection layer, hole transport layer, hole injection and transport layer, light emission layer, electron transport layer, or electron injection layer of the organic light emitting device and provides improved efficiency, low driving voltage, and improved lifetime characteristic. ##STR00001##

An organic electroluminescence device including: an anode, a cathode, and at least one emitting layer between the cathode and the anode, wherein the emitting layer contains a first host material, a second host material, and a dopant material, the first host material is a compound having at least one deuterium atom, and the emitting layer contains the first host material in the proportion of 1% by mass or more.

The present invention provides an organic electroluminescent device, a display panel, and a display apparatus. A light-emitting layer comprises a first compound, a second compound, a third compound, and a fourth compound; the first compound and the second compound form a first exciplex under optical excitation and electric excitation; excitonic energy compounded by the first exciplex can be transferred to the third compound; then the third compound and the second compound are compounded to form a second exciplex; and excitonic energy compounded by the second exciplex can be transferred to the fourth compound. In the excitonic energy transfer process, triplet excitons improve a reverse intersystem crossing process and are converted into singlet excitons to radiate and emit fluorescence when an exciplex is formed by means of compounding; the singlet excitons are effectively used for Forster energy transfer, and Dexter energy transfer is inhibited, such that energy loss is avoided, the excitonic energy is effectively used, and the device efficiency is improved.

An organic electroluminescent device having high efficiency and high driving stability, and a material suitable for the organic electroluminescent device are provided. The material for organic electroluminescent devices comprises an indolocarbazole compound represented by a general formula (1). In the formula, the ring a is represented by a formula (1a), X is NR, S, O or CR.sub.2, and Ar.sup.1 and Ar.sup.2 are an aromatic heterocyclic group represented by a formula (1b). Y is N or CR, and at least one is N. L.sup.1 is an aromatic hydrocarbon group. The material for the organic electroluminescent devices is suitable as material for the host of the light emitting layer or the hole blocking layer of organic EL devices.

##STR00001##

An organometallic compound is represented by Formula 1. A light-emitting device includes a first electrode, a second electrode facing the first electrode, an interlayer disposed between the first electrode and the second electrode and including an emission layer, and at least one organometallic compound represented by Formula 1. An electronic apparatus includes the light-emitting device.