Provided is a semiconductor nanoparticle-containing composition capable of forming a wavelength conversion layer that efficiently converts the wavelength of excitation light and exhibits sufficient luminescence intensity. An aspect of the semiconductor nanoparticle-containing composition of the present invention contains semiconductor nanoparticles (A) and a coloring matter (B) and further contains a polymerizable compound (C), in which the semiconductor nanoparticles (A) have a maximum emission wavelength in the range of 500 to 670 nm over a wavelength range of 300 to 780 nm, and the coloring matter (B) contains at least one selected from coloring matters (B1) to (B5) having specific structures.

Use of transition metal complexes of the formula (I) in organic light-emitting diodes ##STR00001## where: M.sup.1 is a metal atom; carbene is a carbene ligand; L is a monoanionic or dianionic ligand; K is an uncharged monodentate or bidentate ligand selected from the group consisting of phosphines; CO; pyridines; nitriles and conjugated dienes which form a π complex with M.sup.1; n is the number of carbene ligands and is at least 1; m is the number of ligands L, where m can be 0 or ≥1; o is the number of ligands K, where o can be 0 or ≥1; where the sum n+m+o is dependent on the oxidation state and coordination number of the metal atom and on the denticity of the ligands carbene, L and K and also on the charge on the ligands carbene and L, with the proviso that n is at least 1, and also
an OLED comprising these transition metal complexes, a light-emitting layer comprising these transition metal complexes, OLEDs comprising this light-emitting layer, devices comprising an OLED according to the present invention, and specific transition metal complexes comprising atb least two carbene ligands.

A compound having a Pt tetradentate structure of Formula 1, ##STR00001##
is provided. In the structure of Formula 1, rings C and D each independently represent 5- or 6-membered carbocyclic or heterocyclic ring; L.sup.1, L.sup.2, and L.sup.3 are each independently a direct bond, BR, NR, PR, O, S, Se, C═O, S═O, SO.sub.2, SiRR′, GeRR′, alkyl, cycloalkyl, or a combination thereof; the sum of n1 and n2 is 1 or 2; X is selected from NR.sup.E, O, S, and Se; X.sup.3 and X.sup.4 each independently carbon or nitrogen; and one of Q.sup.1, Q.sup.3, and Q.sup.4 is oxygen, and the remaining two of Q.sup.1, Q.sup.3, and Q.sup.4 each represents a direct bond. Formulations and devices, such as an OLEDs, that include the compound of Formula 1 are also described.

Provided are an electroluminescent compound having a structure represented by Formula I, a thermally activated delayed fluorescence material and an application thereof. The electroluminescent compound has TADF characteristics and may be applied to a light emitting layer of an OLED device as a thermally activated delayed fluorescence material. The OLED device includes an anode, a cathode, and at least one organic thin film layer comprising the thermally activated delayed fluorescence material in a light emitting layer between the anode and the cathode. The electroluminescent compound effectively reduces the overlap between HOMO and LUMO through special molecular structure design, so that ΔE.sub.ST is reduced to less than 0.25 eV, which satisfies reverse crossing of energy from a triplet state to a singlet state, effectively improves transmission capacities of two kinds of carriers, improves carrier balance, and thus significantly improves light emitting efficiency of the OLED device.

Provided are an organic electroluminescence device, which shows high luminous efficiency, is free of any pixel defect, and has a long lifetime, and a material for an organic electroluminescence device for realizing the device. The material for an organic electroluminescence device is a compound having a π-conjugated heteroacene skeleton crosslinked with a carbon atom, nitrogen atom, oxygen atom, or sulfur atom. The organic electroluminescence device has one or more organic thin film layers including a light emitting layer between a cathode and an anode, and at least one layer of the organic thin film layers contains the material for an organic electroluminescence device.

The present invention provides a pyrromethene boron complex represented by the general formula (1), a light emitting element material having high luminance efficiency, and a light emitting element:

##STR00001##

wherein X.sup.1 and X.sup.2 each may be the same or different, and are selected from the group consisting of an alkyl group, a cycloalkyl group, a heterocyclic group, an alkenyl group, a cycloalkenyl group, an alkynyl group, a hydroxyl group, a thiol group, an alkoxy group, a cycloalkoxy group, an alkylthio group, an aryl ether group, an aryl thioether group, an aryl group, a heteroaryl group, halogen and a cyano group. These functional groups may further have a substituent. Ar.sup.1 to Ar.sup.4 each may be the same or different, and are a substituted or unsubstituted aryl group, or a substituted or unsubstituted heteroaryl group. The aryl group and the heteroaryl group may be either a monocyclic ring or a fused ring. However, when one or both of Ar.sup.1 and Ar.sup.2 is/are monocyclic ring(s), the monocyclic ring has one or more secondary alkyl groups, one or more tertiary alkyl groups, one or more aryl groups, or one or more heteroaryl groups as substituents, or has a methyl group and a primary alkyl group as two or more substituents in total. R.sup.1 and R.sup.2 each may be the same or different, and are a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heteroaryl group. R.sup.3 to R.sup.5 each may be the same or different, and are selected from the group consisting of a hydrogen atom, an alkyl group, a cycloalkyl group, a heterocyclic group, an alkenyl group, a cycloalkenyl group, an alkynyl group, an aryl group, a heteroaryl group, a hydroxyl group, a thiol group, an alkoxy group, an alkylthio group, an aryl ether group, an aryl thioether group, halogen, a cyano group, an aldehyde group, an acyl group, a carboxyl group, an ester group, an amide group, a sulfonyl group, a sulfonic acid ester group, a sulfonamide group, an amino group, a nitro group, a silyl group, and a ring structure with an adjacent group. These functional groups may further have a substituent. R.sup.6 and R.sup.7 each may be the same or different, and are selected from the group consisting of a hydrogen atom, an alkyl group, a cycloalkyl group, a heterocyclic group, an alkenyl group, a cycloalkenyl group, an alkynyl group, an aryl group, a heteroaryl group, a hydroxyl group, a thiol group, an alkoxy group, an alkylthio group, an aryl ether group, an aryl thioether group, halogen, a cyano group, an aldehyde group, an acyl group, a carboxyl group, an ester group, an amide group, a sulfonyl group,

The present invention generally relates to optoelectronic compounds, including certain nitrobenzoyl compounds, for example 2-(4-nitrobenzoyl)oxazole. In certain embodiments, these compounds can be used as electrochromic media in devices requiring change of optical absorbance or transmittance as a function of applied voltage. Examples of such devices include electrochromic mirrors, windows, displays, or the like. One specific example is solar and thermal control by smart, dynamic windows for energy-efficient buildings. Other embodiments of the invention are generally directed to systems and devices using such compounds, methods of using such compounds, e.g., to control the absorbance or transmittance of light, kits involving such compounds, or the like.

A luminescence device includes a first electrode, a hole transport region disposed on the first electrode, an emission layer disposed on the hole transport region, an electron transport region disposed on the emission layer, and a second electrode disposed on the electron transport region. The hole transport region contains a nitrogen-containing compound represented by Formula 1, and thus, the luminescence device may exhibit long lifespan and high efficiency. The substituents are the same as described in the detailed descriptions.

##STR00001##

A light emitting diode of an embodiment includes a first electrode, a hole transport region disposed on the first electrode, an emission layer disposed on the hole transport region, an electron transport region disposed on the emission layer, and a second electrode disposed on the electron transport region. The hole transport region includes a first hole transport layer disposed adjacent to the first electrode and having a first refractive index, a second hole transport layer disposed adjacent to the emission layer and having a second refractive index, and a third hole transport layer disposed between the first hole transport layer and the second hole transport layer and having a third refractive index which is greater than each of the first refractive index and the second refractive index, thereby showing high light extraction efficiency and high emission efficiency properties.

An organic electroluminescence device includes: a cathode; an anode; and an organic thin-film layer disposed between the cathode and the anode, the organic thin-film layer having one or more layers including an emitting layer, in which the emitting layer includes a first material represented by the following formula (1) and a second material in a form of a fluorescent dopant material. ##STR00001##