Organic electroluminescent device

Abstract

The object of the invention is to provide a material for a highly efficient and highly durable organic EL device, the material having excellent hole injection / transport capability, electron-blocking ability, thin film stability, and durability, and to further provide an organic EL device having high efficiency, low driving voltage, and long service life by combining the material and various organic EL device materials having excellent hole injection / transport capability, electron-blocking ability, thin film stability, and durability, such that the properties of each material can be effectively exhibited. The arylamine compound having a specific structure according to the invention has excellent hole injection / transport capability, thin film stability, and durability, and can thus be selected as a material for a hole transport layer that efficiently transports holes injected from the positive electrode side. Moreover, various organic EL devices obtained by combining materials such as the electron transport material having a specific structure exhibit good device characteristics.

Description

technical field [0001] The present invention relates to an organic electroluminescent element as a self-luminescent element suitable for various display devices, and in detail, relates to an organic electroluminescent element (hereinafter, simply referred to as an organic EL element) using a specific arylamine compound. . Background technique [0002] Since the organic EL element is a self-luminous element, it is brighter than a liquid crystal element, has excellent visibility, and can realize a clear display, so it has been actively studied. [0003] In 1987, C.W.Tang of Eastman Kodak Company developed a laminated structural element in which each material shared various functions, thus making the organic EL element using organic materials a practical element. They laminated a phosphor capable of transporting electrons and an organic substance capable of transporting holes, injected the charges of the two into the phosphor layer to make it emit light, and obtained 1000 cd / m...

AI Technical Summary

Problems solved by technology

Although NPD has good hole transport ability, its glass transition temperature (Tg), which is an indicator of heat resistance, is as low as 96°C, and crystallization under high temperature conditions degrades device characteristics (see, for example, Non-Patent Document 4)

In addition, among the aromatic amine derivatives described in the above-mentioned patent documents, it is known that the mobility of a hole is 10. -3 cm 2 Compounds with excellent mobility above / Vs (for example, refer to Patent Document 1 and Patent Document 2), but due to insufficient electron barrier properties, part of the electrons pass through the light-emitting layer, and improvement in luminous efficiency cannot be expected. Higher efficiency requires materials with higher electron barrier properties, more stable thin films, and high heat resistance

In addition, aromatic amine derivatives with high durability are disclosed (for example, refer to Patent Document 3), but there is no example of using a substance used as a charge transport material for an electrophotographic photoreceptor as an organic EL element.

[0011] As compounds with improved properties such as heat resistance and hole injection properties, arylamine compounds having a substituted carbazole structure have been proposed (for example, refer to Patent Document 4 and Patent Document 5), but when these compounds are used in space In the elements of the hole injection layer and the hole transport layer, although the heat resistance and luminous efficiency have been improved, they are still not sufficient, and further lower driving voltage and higher luminous efficiency are required.

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