Organic light-emitting device with improved layer structure

Abstract

An organic light emitting device having a cathode, an anode and an organic layer structure disposed between the cathode and the anode, the organic layer structure comprising a hole injection layer doped with a p-type dopant, a hole transport layer, an emissive layer and an electron transport layer doped with an n-type dopant, wherein all of the layers in the organic layer structure are substantially made from the same organic host material. In particular, the organic host material is a bipolar organic material such as a derivative of fused aromatic rings. The emissive layer can be doped with a fluorescent dye or a phosphorescent dye.

Description

[0001] This application is a divisional application of and claims priority to a pending U.S. patent application Ser. No. 11 / 014,508, filed Dec. 16, 2004.FIELD OF THE INVENTION [0002] The present invention relates generally to light-emitting devices and, more particularly, to organic light-emitting diodes. BACKGROUND OF THE INVENTION [0003] Organic light-emitting diodes OLEDs are known in the art. For example, Kido et al. (U.S. Pat. No. 6,013,384) discloses, as shown in FIG. 1a, an organic electroluminescent device 10 wherein the organic layers consist of a hole transport layer (HTL) 13, an emissive layer 14 and a metal-doped organic compound layer 15 disposed between an anode layer 12 and a cathode layer 16. The device is fabricated on a substrate 11. According to Kido et al., the organic compounds which can be used in the formation of the emissive layer, the electron transport layer and the metal-doped layer in the OLED device, include polycyclic compounds, condensed polycyclic hyd...

AI Technical Summary

Benefits of technology

"The present invention provides an organic light-emitting diode (OLED) with a reduced number of different materials used in the organic layers. This is achieved by using a bipolar organic material, such as a derivative of fused aromatic rings, as the host material for the emissive layer and the hole transport layer, and doping them with n-type and p-type dopants, respectively. The OLED can be a phosphorescent or fluorescent OLED. The invention also provides a method for fabricating the OLED with the same host material and dopants. The technical effect is to simplify the manufacturing process and improve the efficiency of OLEDs."

Problems solved by technology

In the fabrication of a full-color organic display device, the deposition of the organic layers is complex and costly.

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