White light electrogenerated light-emitting apparatus

Abstract

The invention discloses a white light electrogenerated light-emitting apparatus, which comprises the structure including a substrate, a conductive layer, a hole injecting layer, a hole transmitting layer, an electron stop layer, a light emitting layer, a hole stop layer, an electron transmitting layer, an electron injecting layer and a cathode layer in sequence; the light emitting layer is a composite layer structure, and the composite layer structure comprises the following layers of a red phosphor light emitting layer, a first interval layer, a blue light emitting layer, a second interval layer and a green phosphor light emitting layer in sequence; and the red phosphor light emitting layer is prepared on the surface of the electron stop layer, and the hole stop layer is prepared on the surface of the green phosphor light emitting layer. According to the invention, light emitting layers of blue light emitting materials, red and green light phosphor materials are applied in the white light electrogenerated light-emitting apparatus, red and green light phosphor light emitting layers are respectively arranged on both sides of the blue light emitting layer, therefore the triplet state energy of blue light can be fully captured, and the light emitting efficiency is further increased.

Description

technical field [0001] The invention relates to a white light electroluminescent 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 ac...

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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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