OLED Coating Compound With Curing Groups for Stable Hole Transport
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Solution Overview
Problem
Existing organic light emitting devices face challenges with materials that lack thermal stability, efficient hole and electron transfer, chemical stability, and compatibility with electrodes, leading to high driving voltage, low efficiency, and short device lifetime.
Innovation Solution
A compound represented by Chemical Formula 1, which includes a curing group for solvent compatibility and efficient hole transfer, is used in a coating composition to form organic material layers, enhancing thermal and photostability, reducing driving voltage, and improving light efficiency and device lifetime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If NPB is used as a hole transfer layer material, then the device can be manufactured with conventional materials, but the glass transition temperature is 100°C or lower, making it difficult to use in high current devices
Solution Approach 1:
The patent modifies the molecular structure of hole transfer materials by introducing specific chemical groups and adjusting molecular weight to elevate the glass transition temperature from 100°C or lower (NPB) to above 100°C, thereby improving thermal stability for high current applications
Solution Approach 2:
The patent develops composite hole transfer materials that combine multiple organic compounds with complementary properties, achieving both high glass transition temperature and excellent charge transport performance, resolving the trade-off between thermal stability and electrical functionality
2Ease of manufacture
If PEDOT:PSS is used as a hole transfer material, then the device can be manufactured using solution coating method, but the LUMO energy level is lower than that of light emitting layer materials, causing efficiency and lifetime problems
Solution Approach 1:
The patent carefully adjusts the HOMO and LUMO energy levels of solution-processable hole transfer materials through molecular design, ensuring the LUMO level is higher than that of light emitting layer materials while maintaining solution coating manufacturability, thus resolving the energy level mismatch issue
Solution Approach 2:
The patent introduces intermediate hole transfer materials that act as energy level bridges between the electrode and light emitting layer, with optimized HOMO/LUMO levels that prevent electron leakage while facilitating hole injection, solving the compatibility problem between solution-processed materials and light emitting layers
3Use of energy by moving object
If materials with high charge mobility are used to maximize exciton formation, then light emission efficiency improves, but material deformation caused by moisture or oxygen increases, reducing device stability
Solution Approach 1:
The patent creates composite organic materials combining high-mobility charge transport units with sterically hindered groups that provide excellent chemical stability against moisture and oxygen, achieving both high light emission efficiency and long-term device stability simultaneously
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 compound enables low-voltage operation, high light efficiency, and extended device lifetime, allowing for large-area manufacturing through solution processes.
Implementation Method 1
a compound represented by Chemical Formula 1, which includes a curing group for solvent compatibility and efficient hole transfer
Implementation Method 2
enhancing thermal and photostability
Implementation Method 3
When an organic material layer is placed between an anode and a cathode and a current is applied between the two electrodes, electrons and holes are injected to the organic material layer from the cathode and the anode, respectively. The holes and the electrons injected to the organic material layer recombine to form excitons, and light emits when these excitons fall back to the ground state
Data Source
Figure 1
AI summary
The present specification relates to a compound, a coating composition including the same, and an organic light emitting device.