Rigid 3D Electron Transport Compounds for OLED Lifetime
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Solution Overview
Problem
Conventional electron transport layers in OLED displaying devices suffer from low luminous efficiency and short lifespan, leading to poor user experience.
Innovation Solution
A light emitting device with an electron transport layer comprising a heteroaromatic ring group, a first electron-withdrawing group, and a three-dimensional group having rigidity, with specific energy level and orbital values, to enhance electron injection, stability, and prevent triplet exciton diffusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electron transport layers are used, then the device structure is simple, but the luminous efficiency is low and lifespan is short
Solution Approach 1:
The patent employs composite materials by combining heteroaromatic ring groups with electron-withdrawing groups and three-dimensional rigid groups. This composite structure integrates multiple functional characteristics: the heteroaromatic ring provides electron transport capability, the electron-withdrawing group enhances electron mobility, and the three-dimensional rigid group prevents crystallization and improves stability. This composite approach resolves the contradiction by achieving enhanced reliability through material composition rather than structural complexity.
Solution Approach 2:
The patent applies parameter changes by systematically adjusting molecular structure parameters including introducing specific heteroaromatic ring groups (with nitrogen atoms), controlling the energy levels (T1≥2.3 eV, HOMO: 6.0-7.0 eV, LUMO: 2.6-3.6 eV), and incorporating three-dimensional rigid groups. These parameter modifications optimize the electron transport properties and stability, thereby extending lifespan without requiring complex device architecture.
2Productivity
If conventional electron transport layers are used, then the manufacturing process is simple, but the luminous efficiency is low
Solution Approach 1:
The patent applies segmentation by dividing the electron transport layer material into distinct functional modules: heteroaromatic ring groups for electron transport, electron-withdrawing groups for enhancing mobility, and three-dimensional rigid groups for structural stability. This segmentation allows each component to be optimized independently and facilitates systematic material design, improving luminous efficiency while maintaining manufacturability through modular synthesis approaches.
3Power
If electron transport layer material has high electron mobility, then the voltage is low, but triplet exciton diffusion occurs
Solution Approach 1:
The patent introduces triplet exciton blocking groups as intermediary elements within the electron transport layer material. These groups act as mediators that intercept and block triplet exciton diffusion while allowing electron transport to proceed efficiently. The specific molecular structure with heteroaromatic rings, electron-withdrawing groups, and three-dimensional rigid groups creates an intermediary layer that prevents harmful triplet exciton diffusion without sacrificing electron mobility, thus maintaining low voltage operation.
4Stability of the object's composition
If the electron transport layer material is flexible, then the device can be processed easily, but material crystallization occurs reducing stability
Solution Approach 1:
The patent applies dimensionality change by incorporating three-dimensional rigid groups into the molecular structure. These groups introduce spatial dimensionality that prevents molecular packing and crystallization, thereby enhancing material stability. The three-dimensional rigid groups create steric hindrance that maintains amorphous structure even during device processing, resolving the contradiction between processability and stability without requiring overly complex molecular designs.
Data Source
AI summary
A compound, a light emitting device, and a displaying device, which relates to the technical field of displaying. The light emitting device has a high luminous efficiency and a long life. The light emitting device includes an electron transport layer, and the material of the electron transport layer includes a heteroaromatic ring group including at least one nitrogen atom, a first electron-withdrawing group, and at least one three-dimensional group having a rigidity. The triplet-state energy level T1 of the material of the electron transport layer satisfies T1≥2.3 eV. The absolute value of the energy value of the highest occupied molecular orbital HOMO of the material of the electron transport layer satisfies 6.0 eV≤|HOMO|≤7.0 eV. The absolute value of the energy value of the lowest unoccupied molecular orbital LUMO of the material of the electron transport layer satisfies 2.6 eV≤|LUMO|≤3.6 eV.