Organic Light Emitting Device Block Copolymer Layer
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Solution Overview
Problem
Existing light emitting devices, such as organic electroluminescent devices, face challenges in achieving sufficient luminance life.
Innovation Solution
A light emitting device is designed with a specific configuration including an anode, a cathode, and two organic layers, where the first layer contains a phosphorescent compound and the second layer comprises a block copolymer with specific constitutional units, including non-crosslinkable and crosslinkable units, to enhance charge transport and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If a conventional hole transporting layer containing only polymer compound or cured product is used, then the device structure is simple, but the luminance life is insufficient
Solution Approach 1:
The hole transporting layer is segmented into two distinct layers: a first hole transporting layer containing a phosphorescent compound and a polymer compound, and a second hole transporting layer containing a block copolymer with crosslinkable groups. This segmentation allows each layer to perform specific functions optimally, thereby extending luminance life while maintaining manageable structural complexity.
Solution Approach 2:
The invention employs composite materials in both hole transporting layers. The first layer combines phosphorescent compounds with polymer compounds, while the second layer uses block copolymers with crosslinkable groups. These composite structures enhance device performance and durability, directly addressing the luminance life issue without excessive complexity.
2Reliability
If the second organic layer contains block copolymer with crosslinkable groups, then charge transport is enhanced, but the manufacturing process becomes more complex
Solution Approach 1:
The block copolymer's crosslinkable groups undergo parameter changes through controlled crosslinking reactions. By adjusting crosslinking density and using appropriate catalysts, the invention optimizes charge transport performance while keeping the manufacturing process manageable through standard organic electronics fabrication techniques.
3Stability of the object's composition
If non-crosslinkable constitutional units are included in the block copolymer, then stability is improved, but the crosslinking efficiency is reduced
Solution Approach 1:
The block copolymer is designed with local quality variation: specific blocks contain crosslinkable groups for efficient crosslinking, while other blocks contain non-crosslinkable constitutional units for stability. This localized functional differentiation allows simultaneous optimization of crosslinking efficiency and layer stability without compromising either property.
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 device exhibits improved luminance life due to the optimized layer structure and material composition, which effectively enhances charge transport and stability.
Implementation Method 1
the first organic layer is a layer comprising a phosphorescent compound
Data Source
Figure 1
AI summary
Provided is a light emitting device having an anode, a cathode, and a first organic layer and a second organic layer provided between the anode and the cathode, wherein the first organic layer is a layer containing a phosphorescent compound, the second organic layer contains at least one of a block copolymer containing an end group, a block that binds to the end group and a block that does not bind to the end group, and a crosslinked product of the block copolymer, the non-terminal block contains at least one constitutional unit selected from the group consisting of a non-crosslinkable constitutional unit represented by the formula (X) and a non-crosslinkable constitutional unit represented by the formula (Z), and at least one of XI > XII; ZI > ZII; XI+ZI > XII+ZII is satisfied when the total number of the non-crosslinkable constitutional unit represented by the formula (X) and the total number of the non-crosslinkable constitutional unit represented by the formula (Z) in the non-terminal block are represented by XI and ZI, respectively, and the total number of the non-crosslinkable constitutional unit represented by the formula (X) and the total number of the non-crosslinkable constitutional unit represented by the formula (Z) in the terminal block are represented by XII and ZII, respectively.