White Organic Electroluminescent Device with Rare Earth Complex Doping
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Solution Overview
Problem
Current white organic electroluminescent devices face challenges with low light-emitting effectiveness, brightness, spectral stability, and high operating voltage due to unbalanced carrier injection and complex structures, which also increase manufacturing costs.
Innovation Solution
A white organic electroluminescent device is designed with specific layer structures and material compositions, including an electron-dominated light-emitting layer with a rare earth complex and balanced doping concentrations of blue, green, and red organic light-emitting materials, to achieve efficient energy transfer and balanced carrier distribution, improving light-emitting effectiveness, spectral stability, and reducing operating voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If multiple light-emitting layers with different dopants are used to achieve white light emission, then color coverage is improved, but device structure complexity increases and manufacturing cost rises
Solution Approach 1:
The patent combines multiple light-emitting materials (blue, green, red phosphorescent materials) and host materials into a single integrated light-emitting layer, eliminating the need for multiple separate layers. This merging approach achieves complete spectral coverage while simplifying the device structure and reducing manufacturing complexity.
Solution Approach 2:
The patent employs composite material systems where phosphorescent emitting materials are doped into host materials to form a unified light-emitting layer. This composite approach enables simultaneous achievement of broad spectral coverage, high efficiency, and structural simplicity through careful selection and combination of materials with complementary properties.
2Use of energy by moving object
If trivalent iridium complexes are used to improve light-emitting effectiveness, then luminous efficiency increases, but carrier injection balance deteriorates leading to high operating voltage
Solution Approach 1:
The patent applies local quality by selecting specific host materials with appropriate energy levels and carrier transport properties for different regions of the light-emitting layer. The host materials are chosen to locally optimize both energy transfer efficiency to the phosphorescent dopants and carrier injection balance, resolving the contradiction between high luminous efficiency and low operating voltage.
Solution Approach 2:
The patent optimizes parameters such as doping concentrations of phosphorescent materials, host material selection, and energy level matching to achieve simultaneous improvement in light-emitting effectiveness and carrier injection balance. By carefully adjusting these parameters, the device achieves high efficiency with balanced carrier injection and reduced operating voltage.
3Use of energy by moving object
If double light-emitting layers are used to combine blue-green and orange-red light, then light-emitting effectiveness improves, but spectral coverage is insufficient resulting in low color restoration coefficient
Solution Approach 1:
The patent merges blue, green, and red phosphorescent emitting materials within a single light-emitting layer, achieving complete spectral coverage from 400-700nm. This unified approach ensures comprehensive spectral coverage and high color restoration coefficient while maintaining high light-emitting effectiveness through optimized energy transfer from host to dopant materials.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution results in enhanced light-emitting effectiveness, improved spectral stability, reduced operating voltage, and extended service life, while maintaining balanced photon distribution for white light emission.
Implementation Method 1
When charges are injected into an organic layer between a hole injection electrode and an electron injection electrode, electrons and holes encounter, combined, and then annihilated, and thus light is generated
Implementation Method 2
a host, a blue emitting material and an assisting dopant... The organic electroluminescent device has high light-emitting effectiveness
Data Source
Figure 1~2
Figure 3~4
AI summary
Provided is a white organic electroluminescent device, composed of a substrate (1), an anode layer (2), an anode modification layer (3), a hole transporting-electron blocking layer (4), a hole-dominated light-emitting layer (5), an electron-dominated light-emitting layer (6), a hole blocking-electron transporting layer (7), a cathode modification layer (8), and a cathode layer (9) arranged in turn, wherein the electron-dominated light-emitting layer (6) is composed of an organic sensitive material, a blue organic light-emitting material, and an electron-type organic host material. A rare earth complex having a matched energy level, such as Tm(acac)3Phen or Dy(acac)3phen is selected as the organic sensitive material, and a trace amount of the same is doped into the electron-dominated light-emitting layer (6), which has the function of an energy transporting ladder and a deep binding center for charge carriers, so as to improve the light-emitting effectiveness, spectral stability, and service life of the device, reduce the operating voltage of the device, and delay the attenuation of the effectiveness of the device.