The electroluminescent element includes a QD layer and a hole transport layer. QD phosphor particles contained in the QD layer are nanocrystals containing zinc and selenium, or zinc, selenium, and sulfur. A fluorescent half width of the QD phosphor particles is 25 nm or less, and a fluorescent peak wavelength of the QD phosphor particles is 410 nm or more and 470 nm or less. The hole transport layer includes poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4′-(N-(4-sec-butylphenyl)diphenylamine)]. A film thickness of the hole transport layer is 10 nm or more and 57 nm or less.

A copolymer, including a structural unit represented by Chemical Formula 1, a structural unit represented by Chemical Formula 2, or a combination thereof:

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wherein R.sub.1, R.sub.2, R.sub.3, X.sub.1, X.sub.2, and Ar.sub.1 are as provided herein.

A composition which is useful for producing a light emitting device having excellent external quantum efficiency and a light emitting device containing the composition are described. The light emitting device contains an anode, a cathode, and an organic layer disposed between the anode and the cathode and contains a composition containing at least two compounds (A) selected from the group consisting of a compound represented by the formula (FH) and a polymer compound containing a constitutional unit having a group obtained by removing from a compound represented by the formula (FH) one or more hydrogen atoms, and a compound (B) having a condensed hetero ring skeleton (b) containing a boron atom and a nitrogen atom in the ring.

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A copolymer including a structural unit represented by Chemical Formula 1

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wherein the copolymer is capable of improving luminous efficiency and durability, particularly, an improvement in luminescence life-span, of an electroluminescence device, particularly a quantum dot electroluminescence device.

The present disclosure relates to a light-emitting diode (LED) in which an organic compound including an imidazolium-based cationic moiety and an amine-based anionic moiety substituted with a strong electron-withdrawing group such as a sulfonyl group or a cyano group is applied to a hole transfer layer, and a light-emitting device. By applying the organic compound according to the present disclosure to the hole transfer layer, an energy barrier between the hole transport layer and an emitting material layer is removed, and an LED having improved hole transport properties can be designed. Therefore, it is possible to realize and manufacture an LED and a light-emitting device, driven at a low voltage and having improved luminous efficiency.

A charge-transfer salt formed from a material comprising a repeat unit of formula (I) and an n-dopant: wherein BG is a backbone group of the repeat unit; R.sup.1 is a ionic substituent comprising at least one cationic or anionic group; n is at least 1; R.sup.2 is a non-ionic substituent; and m is 0 or a positive integer; the material further comprising a counterion balancing the charge of the cationic or anionic group. ##STR00001##

Provided are a composition for forming an organic light-emitting device, a method of preparing an organic light-emitting device, and an organic light-emitting device. The method of preparing an organic light-emitting device includes: forming an organic layer including an emission layer on a first electrode, wherein the forming of the organic layer includes performing a solution process using a composition for forming an organic light-emitting device, the composition for forming an organic light-emitting device includes n kinds of solvent, a solvent (Sv.sub.1) having the highest boiling point among the n kinds of solvent and a solvent (Sv.sub.2) having the second highest boiling point among the n kinds of solvent satisfy Equation 1, n is an integer from 2 to 10, and the solvent (Sv.sub.1) having the highest boiling point among the n kinds of solvent is a compound represented by Formula 1.

The present invention relates to a formulation comprising at least one crosslinkable polymer and at least one organic solvent, wherein the at least one crosslinkable polymer is contained in the formulation in a concentration of at least 0.5 g/L, wherein the at least one organic solvent has a boiling point of at least 200° C., characterized in that the solubility of the at least one crosslinkable polymer in the at least one organic solvent is such that the crosslinkable polymer at a concentration of 30 g/L starts to precipitate if 60 vol.-% or less of ethanol is added to the formulation, to the use of these formulations for the preparation of electronic or optoelectronic devices, to a process for the preparation of electronic or optoelectronic devices using these formulations as well as to electronic or optoelectronic devices.

A composition which is useful for production of a light emitting device excellent in light emission efficiency is provided. In particular, provided is a composition containing a compound represented by formula (1) and a phosphorescent compound, wherein R.sup.1 and R.sup.2 each independently represent a substituent, n.sup.1 represents an integer of 1 to 14, and Ar.sup.1 represents an arylene group or a divalent heterocyclic group, and at least one of one or more groups Ar.sup.1 is a group represented by the formula (1-A), wherein the variable groups R.sup.1A to R.sup.8A, R.sup.91A, and R.sup.92A are as defined in the specification. ##STR00001##

An organic light-emitting device includes: a first electrode; a second electrode facing the first electrode; an emission layer between the first electrode and the second electrode; a hole transport region between the first electrode and the emission layer; and an electron transport region between the emission layer and the second electrode, the electron transport region including an electron auxiliary layer, wherein the hole transport region includes at least one copolymer selected from i) a first copolymer of a first compound and a second compound and ii) a second copolymer of a third compound and a fourth compound, wherein the first compound and the second compound are each independently selected from compounds represented by Formula 1, and the third compound and the fourth compound are each independently selected from compounds represented by Formula 2, and wherein the electron auxiliary layer includes a metal oxide. ##STR00001##