Color-adjustable organic electroluminescent device and preparation method thereof

A technology of luminescence and organic electronics, which is applied in the field of color-tunable organic electroluminescent devices and their preparation, can solve the problems of reducing device current density, device luminous efficiency attenuation, and high operating voltage, so as to improve recombination probability and efficiency, improve The effect of transmission ability and delay attenuation

Active Publication Date: 2009-10-21
CHANGCHUN INST OF APPLIED CHEMISTRY - CHINESE ACAD OF SCI
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

It can be seen that after years of hard work, although the problems of poor color purity and low efficiency of the device have been alleviated to a certain extent, the problems of low brightness and high operating voltage of the device have not been substantially improved.
[0004] One of the fundamental reasons for the low brightness and high operating voltage of blue and blue-green organic electroluminescent devices is that blue and blue-green organic light-emitting materials have a relatively high energy gap.
Usually, a high energy gap is accompanied by a higher lowest unoccupied molecular orbital or a lower highest occupied molecular orbital, which leads to an excessively high electron injection barrier or hole injection barrier in the device, resulting in insufficient electron injection or hole injection in the light-emitting region. Insufficient injection
As a result, the unbalanced carrier injection leads to a lower recombination probability of the device, which ultimately affects the luminous efficiency of the device
On the other hand, the unbalanced carrier injection leads to the device's light-emitting region is often close to the interface of the organic layer, and is very narrow
The narrow luminescent range leads to severe quenching due to excessive exciton concentration, which in turn causes the luminous efficiency of the device to decay rapidly with the increase of current density; as a result, blue and blue-green organic electroluminescent devices usually have high current density Very low efficiency, which further limits the improvement of device brightness
In addition, too high electron injection barrier or hole injection barrier will increase the working voltage of the device and reduce the current density of the device, thereby accelerating the decay of efficiency and the aging of the device, which is also the cause of blue and blue-green organic electroluminescence. Important reasons for problems such as low brightness and high operating voltage of light-emitting devices

Method used

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  • Color-adjustable organic electroluminescent device and preparation method thereof
  • Color-adjustable organic electroluminescent device and preparation method thereof
  • Color-adjustable organic electroluminescent device and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038] Firstly, the ITO anode layer on the ITO glass is chemically etched into strip electrodes with a width of 10 mm and a length of 30 mm, and then ultrasonically cleaned with cleaning solution and deionized water for 15 minutes and dried in an oven. Then put the dried substrate into the pretreatment vacuum chamber, and then transfer the ITO anode to the organic evaporation chamber after 10 minutes of low-pressure oxygen plasma treatment with a voltage of 400 volts in an atmosphere of 10 Pa. In a vacuum of 1-5 x 10 -5 In Pa's organic evaporation chamber, a 50-nm-thick AlQ-doped NPB hole-transport layer / luminescent layer, a 30-nm-thick BCP hole-blocking layer, and a 30-nm-thick AlQ electron-transport layer were sequentially evaporated on the ITO layer . Next, the unfinished devices are transferred to a metal evaporation chamber at 5-8 x 10 -5 A 1.0-nm-thick LiF buffer layer was evaporated under a vacuum atmosphere of Pascal, and finally a 100-nm-thick metal Al electrode was...

Embodiment 2

[0040] Firstly, the ITO anode layer on the ITO glass is chemically etched into strip electrodes with a width of 10 mm and a length of 30 mm, and then ultrasonically cleaned with cleaning solution and deionized water for 15 minutes and dried in an oven. Then put the dried substrate into the pretreatment vacuum chamber, and then transfer the ITO anode to the organic evaporation chamber after 10 minutes of low-pressure oxygen plasma treatment with a voltage of 400 volts in an atmosphere of 10 Pa. In a vacuum of 1-5 x 10 -5 In Pa's organic evaporation chamber, a 40-nm-thick AlQ-doped NPB hole-transport layer / luminescent layer, a 30-nm-thick BCP hole-blocking layer, and a 30-nm-thick AlQ electron-transport layer were sequentially evaporated on the ITO layer. . Next, the unfinished devices are transferred to a metal evaporation chamber at 5-8 x 10 -5 A 1.0 nm-thick LiF buffer layer was evaporated under a vacuum atmosphere of Pascal, and finally a 100 nm-thick metal Al electrode wa...

Embodiment 3

[0042] Firstly, the ITO anode layer on the ITO glass is chemically etched into strip electrodes with a width of 10 mm and a length of 30 mm, and then ultrasonically cleaned with cleaning solution and deionized water for 15 minutes and dried in an oven. Then put the dried substrate into the pretreatment vacuum chamber, and then transfer the ITO anode to the organic evaporation chamber after 10 minutes of low-pressure oxygen plasma treatment with a voltage of 400 volts in an atmosphere of 10 Pa. In a vacuum of 1-5 x 10 -5 In Pa's organic evaporation chamber, a 50-nm-thick AlQ-doped NPB hole-transport layer / luminescent layer, a 30-nm-thick BCP hole-blocking layer, and a 30-nm-thick AlQ electron-transport layer were sequentially evaporated on the ITO layer . Next, the unfinished devices are transferred to a metal evaporation chamber at 5-8 x 10 -5 A 1.0 nm-thick LiF buffer layer was evaporated under a vacuum atmosphere of Pascal, and finally a 100 nm-thick metal Al electrode was...

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Abstract

The invention belongs to a color-adjustable organic electroluminescent device and a preparation method thereof. The preparation method adopts a vacuum evaporation plating process and balances the capability of carrier injection by incorporating organic electron transport materials, thereby increasing the recombination probability of the device. In addition, the incorporation of the organic electron transport materials can widen luminescent intervals, weaken exciton quenching and then ease the attenuation of the luminescent efficiency of the device. The luminescent color of the device is adjusted by adjusting the concentration of the organic electron transport materials in a luminescent layer, wherein the organic electroluminescent device displays blue luminescence when the weight ratio of the organic electron transport materials to a main organic blue luminescent material is controlled to be between 0.1 and 0.3 percent, and the device displays aquamarine blue luminescence when the weight ratio of the organic electron transport materials to a main organic blue luminescent material is between 0.4 and 0.8 percent. The device has the maximum current efficiency of 4.77 cd / A, the maximum power efficiency of 3.35 lm / W and the maximum brightness of 22,420 cd / m.

Description

technical field [0001] The invention relates to a color-tunable organic electroluminescent device and a preparation method thereof. Background technique [0002] Organic electroluminescent display is a new type of display technology that is gradually becoming mature in the field of optoelectronic devices and has great practical prospects. Compared with other flat display technologies such as liquid crystal displays, plasma display devices, and field emission displays, organic electroluminescent displays have the advantages of adjustable luminous color, active luminescence, high brightness, high efficiency, wide viewing angle, low energy consumption, simple preparation process, It can produce a series of excellent characteristics such as curved and flexible display screens, and has broad application prospects in the field of large flat panel full-color displays, and is generally considered to be the most competitive new generation display technology. Therefore, the research ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01L51/50H01L51/52H01L51/54H01L51/56C07D215/30C07C211/54C07C211/57C07D209/86C07D471/04
Inventor 张洪杰周亮郭智勇冯婧
Owner CHANGCHUN INST OF APPLIED CHEMISTRY - CHINESE ACAD OF SCI
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