Electroluminescence element

Abstract

An EL element includes, between an anode and a cathode, an emissive element layer including a plurality of emissive layers. The emissive element layer includes two or more organic layers containing a hole transporting compound, and one or more of the plurality of emissive layers contain the hole transporting compound. The concentration of the hole transporting compound in the organic layer which is formed closest to the electron injecting electrode among the organic layers containing the hole transporting compound is lower than the concentration of the hole transporting compound in the organic layer which is formed closest to the hole injecting electrode. When three or more organic layers contain a hole transporting compound, the concentration of the hole transporting compound contained in each organic layer can be set such that, as the organic layer is further away from the hole injecting electrode, the concentration is lower. With this setting, the supply amount and supply timing of holes and electrons can be optimized easily with regard to each of the plurality of emissive layers, so that uniform light emission can be generated in any one of the emissive layers.

Description

[0001] This application is a divisional application of a Chinese patent application with the application number 200510107946.9, the application date is September 30, 2005, the applicant is "Sanyo Electric Co., Ltd.", and the invention name is "Electroluminescent Element". technical field [0002] The present invention relates to the configuration of an electroluminescence (EL) element. Background technique [0003] In recent years, for display elements such as flat-panel display devices and light sources, self-luminous electroluminescent elements have attracted great attention, especially the organic compound materials used can emit a variety of luminescent colors and can achieve high-brightness luminescence. Organic electroluminescent elements, the related research is actively carried out. [0004] The organic electroluminescent element is a light-emitting element layer including a light-emitting layer is provided between a hole injection electrode (anode) and an electron i...

AI Technical Summary

Problems solved by technology

However, it is difficult to make each layer of the multi-layer light-emitting layer emit light efficiently, and the gap between the light-emitting color and the reference white is not small.

[0006] In addition, although organic electroluminescence devices can generally emit light with high brightness, there are still problems such as the durability of organic materials such as light-emitting molecules, and the lifetime of the device is still insufficient.

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