Organic Light-Emitting Device Hole Transport Layer Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current organic light emitting devices face challenges in achieving high efficiency, long lifespan, and thermal stability due to limitations in materials used for hole transport and electron transport layers, particularly with NPB and PEDOT:PSS, which have low glass transition temperatures and inappropriate energy levels, leading to issues with charge mobility and stability.
Innovation Solution
Incorporating an alkali metal complex docked to heteroatoms, phosphine oxide, thioxophosphine, or selenoxophosphine groups in heteroaryl-based compounds within the organic material layers to enhance energy levels, stability, and charge mobility, thereby improving the device's lifespan and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If NPB is used as hole transport layer material, then the device can be manufactured with conventional materials, but the glass transition temperature is low (100°C or lower) making it difficult to apply to high current devices
Solution Approach 1:
The patent modifies the molecular structure of hole transport materials by introducing specific chemical groups and substituents to increase the glass transition temperature while maintaining charge transport properties. This allows the material to withstand higher temperatures generated by high current operation.
Solution Approach 2:
The patent develops composite organic materials combining multiple functional groups and substituents to achieve both high glass transition temperature and effective hole transport capability, resolving the contradiction between thermal stability and charge transport efficiency.
2Ease of manufacture
If PEDOT:PSS is used as hole transport material, then the device can be manufactured by solution coating method, but the LUMO energy level is lower than light emitting layer material making it difficult to achieve high efficiency and long lifespan
Solution Approach 1:
The patent adjusts the HOMO and LUMO energy levels of hole transport materials through molecular design and substituent selection to ensure proper energy level alignment with the light emitting layer, enabling efficient charge injection while maintaining solution processability.
3Device complexity
If conventional organic materials are used, then the device structure is simple, but the thermal stability is insufficient due to low glass transition temperature
Solution Approach 1:
The patent systematically modifies molecular parameters including glass transition temperature, charge mobility, and energy levels through controlled introduction of substituents and functional groups, achieving high thermal stability while maintaining device performance.
4Productivity
If materials with appropriate energy levels are selected, then charge transport efficiency improves, but the thermal stability and electrochemical stability may be compromised
Solution Approach 1:
The patent designs composite organic materials incorporating multiple functional groups that work synergistically to provide both efficient charge transport through appropriate energy levels and high thermal/electrochemical stability through robust molecular structures.
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 proposed solution significantly increases the lifespan of organic light emitting devices by altering the dipole moment of the compounds in the material layers, enhancing thermal stability and charge transport, resulting in improved performance and longevity.
Implementation Method 1
one or more of the organic material layers comprises a compound where an alkali metal complex is docked to one or more of a heteroatom, O of a phosphine oxide group (-P=O), S of a thioxophosphine group (-P=S) or Se of a selenoxophosphine group (-P=Se) of one or more compounds of a heteroaryl-based compound by a London dispersion force or a dipole-induced dipole force
Implementation Method 2
one or more of the organic material layers comprises a compound where an alkali metal complex is docked to one or more of a heteroatom, O of a phosphine oxide group (-P=O), S of a thioxophosphine group (-P=S) or Se of a selenoxophosphine group (-P=Se) of one or more compounds of a heteroaryl-based compound by a London dispersion force or a dipole-induced dipole force
Implementation Method 3
An organic light emitting phenomenon is an example of a conversion of current into visible rays by an internal process of a specific organic molecule. When an organic material layer is interposed between an anode and a cathode, if voltage is applied between two electrodes, electrons and holes are injected from the cathode and the anode to the organic material layer. The electrons and the holes injected into the organic material layer are recombined to form an exciton, and the exciton is reduced to a bottom state to emit light.
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The present invention provides an organic light emitting device comprising a first electrode, a second electrode, and one or more organic material layers disposed between the first electrode and the second electrode, and having an excellent life-span property by changing a dipole moment of a compound comprised in the organic material layers.