The present invention provides for organometallic and organic dopants suitable for use in organic carrier transporting materials. Also provided are organic light emitting devices containing doped organic carrier transporting materials.

An organic light emitting device having an anode, a cathode and an organic layer disposed between the anode and the cathode is provided. In one aspect, the organic layer comprises a compound having at least one zwitterionic carbon donor ligand. In another aspect, the organic layer comprises a carbene compound, including the following:

##STR00001##

In another aspect, the organic layer comprises a carbene compound, including:

##STR00002##

In another aspect, the organic layer comprises a carbene compound that includes a triazole ring and has the structure:

##STR00003##

In another aspect, the organic layer comprises a carbene compound that includes a tetrazole ring and has the structure:

##STR00004##

An organic light emitting diode (OLED) architecture in which efficient operation is achieved without requiring a blocking layer by locating the recombination zone close to the hole transport side of the emissive layer. Aryl-based hosts and Ir-based dopants with suitable concentrations result in an efficient phosphorescent OLED structure. Previously, blocking layer utilization in phosphorescent OLED architectures was considered essential to avoid exciton and hole leakage from the emissive layer, and thus keep the recombination zone inside the emissive layer to provide high device efficiency and a pure emission spectrum.

There is provided a light emitting device which enables a color display with good color balance. A triplet compound is used for a light emitting layer of an EL element that emits red color, and a singlet compound is used for a light emitting layer of an EL element that emits green color and a light emitting layer of an EL element that emits blue color. Thus, an operation voltage of the EL element emitting red color may be made the same as the EL element emitting green color and the EL element emitting blue color. Accordingly, the color display with good color balance can be realized.

An organic light emitting device including: a substrate; a first electrode; a second electrode; and an organic layer interposed between the first electrode and the second electrode and including an emission layer, wherein one of the first electrode and the second electrode is a reflective electrode and the other is a semitransparent or transparent electrode, and wherein the organic layer includes a layer having at least one of the compounds having at least one carbazole group, and a flat panel display device including the organic light emitting device. The organic light emitting device has low driving voltage, excellent current density, high brightness, excellent color purity, high efficiency, and long lifetime.

A novel substance with which an increase in life and emission efficiency of a light-emitting element can be achieved is provided. A carbazole compound having a structure represented by General Formula (G1) is provided. Note that a substituent which makes the HOMO level and the LUMO level of a compound in which a bond of the substituent is substituted with hydrogen deep and shallow, respectively is used as each of substituents in General Formula (G1) (R.sup.1, R.sup.2, Ar.sup.3, and ?.sup.3). Further, a substituent which makes the band gap (Bg) and the T1 level of a compound in which a bond of the substituent is substituted with hydrogen wide and high is used as each of the substituents in General Formula (G1) (R.sup.1, R.sup.2, Ar.sup.3, and ?.sup.3). ##STR00001##

Organometallic compounds comprising an imidazole carbene ligand having a N-containing ring fused to the imidazole ring are provided. In particular, the N-containing ring fused to the imidazole ring may contain one nitrogen atom or more than one nitrogen atom. These compounds may demonstrate high photoluminescent (PL) efficiency, Gaussian emission spectra, and/or short excited state lifetimes. These materials may be especially useful as blue phosphorescent emitters.

An organic light emitting device having an anode, a cathode and an organic layer disposed between the anode and the cathode is provided. In one aspect, the organic layer comprises a carbene compound ##STR00001##

An organic electroluminescence device having a layer of an organic light emitting medium which comprises (A) a specific arylamine compound and (B) at least one compound selected from specific anthracene derivatives, spirofluorene derivatives, compounds having condensed rings and metal complex compounds and is disposed between a pair of electrodes and an organic light emitting medium comprising the above components (A) and (B) are provided. The organic electroluminescence device exhibits a high purity of color, has excellent heat resistance and a long life and efficiently emits bluish to yellowish light. The organic light emitting medium can be advantageously used for the organic electroluminescence device.

An organic light emitting device including: a substrate; a first electrode; a second electrode; and an organic layer interposed between the first electrode and the second electrode and including an emission layer, wherein one of the first electrode and the second electrode is a reflective electrode and the other is a semitransparent or transparent electrode, and wherein the organic layer includes a layer having at least one of the compounds having at least one carbazole group, and a flat panel display device including the organic light emitting device. The organic light emitting device has low driving voltage, excellent current density, high brightness, excellent color purity, high efficiency, and long lifetime.