A white electroluminescent device

Abstract

The invention belongs to the optoelectronic device field and discloses a white-light electroluminescent device. The device possesses a layer structure. The layer structure successively comprises: a substrate / a conducting layer / a hole injection layer / a hole transporting layer / an electronic barrier layer / a luminescent layer / a hole barrier layer / an electronic transmission layer / an electronic injecting layer / a cathode layer. The device is characterized in that: a material of the luminescent layer is a beryllium complex material which is doped with a blue-light phosphorescent material, a red-light phosphorescent material and a green-light phosphorescent material. In the white-light electroluminescent device of the invention, three kinds of phosphorescent materials, which are the blue-light phosphorescent material, the green-light phosphorescent material and the red-light phosphorescent material, are co-doped to the beryllium complex, which is taken as the luminescent layer. Therefore, an electronic transmission ability can be further improved. Because of co-doping, the energy can be avoided performing energy transfer loss among the blue-light phosphorescent material, the green-light phosphorescent material and the red-light phosphorescent material so that a luminescence property of the luminescent layer can be increased.

Description

technical field [0001] The invention relates to the field of optoelectronic devices, in particular to a white light electroluminescence device. Background technique [0002] In 1987, C.W.Tang and Van Slyke of EastmanKodak Company in the United States reported a breakthrough in the research of organic electroluminescence. A high-brightness, high-efficiency double-layer organic electroluminescent device (OLED) was prepared by using ultra-thin film technology. In this double-layer structure device, the brightness reaches 1000cd / m at 10V 2 , its luminous efficiency is 1.51lm / W, and its lifespan is more than 100 hours. [0003] The principle of OLED light emission is based on the action of an external electric field, electrons are injected from the cathode to the lowest unoccupied molecular orbital (LUMO) of organic matter, and holes are injected from the anode to the highest occupied orbital (HOMO) of organic matter. Electrons and holes meet, recombine, and form excitons in t...

AI Technical Summary

Problems solved by technology

[0004] Luminescent materials are the most important factor affecting luminous efficiency. Luminescent materials can be divided into fluorescent materials (ie, blue phosphorescent materials) and phosphorescent materials (ie, red phosphorescent materials and / or green light materials). Fluorescent materials are blocked due to triplet transitions. Therefore, it can only emit light through the radiation inactivation of the singlet state, and the ratio of the triplet excitons to the singlet excitons is about 3:1; and since only 25wt% of the excitons in the fluorescent material can be effectively used, the remaining 75wt % are all through non-radiative attenuation, the energy is released in the form of heat, which increases the temperature of the device, thereby reducing the life of the device, while the phosphorescent material is due to the strong spin coupling effect of the metal atom itself, so the original impossible three-line Therefore, the luminous efficiency is greatly improved. At present, the luminous efficiency of green phosphorescent materials and red phosphorescent materials is relatively good, and the material stability is high, while the life and stability of blue phosphorescent materials are not very good. blue glow

Images