Electroluminescence device

Abstract

The invention discloses an electroluminescence device, which structurally and sequentially includes a substrate / a conducting layer / a hole injection layer / a hole transmission layer / an electronic blocking layer / a luminous layer / a hole blocking layer / an electronic transmission layer / an electronic injection layer / a cathode layer, wherein the luminous layer adopts a composite layer structure; the composite layer structure sequentially includes a first blue light luminous layer / a first quantum well / a red light-green light phosphorescence luminous layer / a second quantum well / a second blue light luminous layer; the first blue light luminous layer is prepared on the surface of the electronic blocking layer; and the hole blocking layer is prepared on the surface of the second blue light luminous layer. According to the electroluminescence device provided by the invention, the first and the second blue light luminous layers are placed on the two sides of the red light-green light phosphorescence luminous layer respectively, so that the illumination of the red light and the green light can be completely excited by the emitted blue light, the energy utilization ratio is improved, and further the luminous efficiency can be enhanced.

Description

technical field [0001] The invention relates to an electroluminescence device. Background technique [0002] In 1987, C.W.Tang and Van Slyke of Eastman Kodak 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 the light-emitting layer. Excitons migrate under the action of an...

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Problems solved by technology

[0004] Luminescent materials are the most important factor affecting luminous efficiency. Luminescent materials can be divided into fluorescent materials and phosphorescent materials. Fluorescent materials are blocked by triplet transitions, so they can only emit light through radiation inactivation of singlet states. Triplet excitons and The ratio of singlet excitons is about 3:1; since only 25% of the excitons in the fluorescent material can be effectively used, the remaining 75% are attenuated by non-radiation, and the energy is released in the form of heat, which increases the temperature of the device , thereby reducing the life of the device, and the phosphorescent material is due to the strong spin coupling effect of the metal atom itself, so the triplet transition that was impossible before becomes possible, so the luminous efficiency is greatly improved. Currently, green phosphorescent materials and red phosphorescent materials The luminous efficiency of phosphorescent materials is relatively good, and the material stability is relatively high, while the life and stability of blue phosphorescent materials are not very good, which restricts the luminescence of blue light.

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