Organic Electroluminescence Anode Surface Treatment
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Solution Overview
Problem
Current organic electroluminescence elements face challenges in achieving low drive voltage, long service life, and good durability due to issues with surface treatment methods, particularly with oxidizing gases leading to increased voltage and reduced durability.
Innovation Solution
A method involving surface treatment of the anode using non-oxidizing gases like argon, nitrogen, or deuterium, followed by forming a p-doped hole-injection layer without exposure to air, to reduce the work function and enhance durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If oxygen plasma treatment is used for surface treatment, then organic matter on the electrode is decomposed and washed away, but the work function of the electrode increases leading to higher drive voltage
Solution Approach 1:
The invention changes the chemical composition parameter of the surface treatment gas from oxidizing (oxygen) to non-oxidizing (nitrogen, argon, carbon dioxide, or their mixtures). This parameter change modifies the surface properties of the electrode to reduce work function while maintaining cleaning effectiveness, thereby resolving the contradiction between durability improvement and drive voltage reduction
Solution Approach 2:
The invention introduces a hole-injection layer as an intermediary component between the electrode and the organic light-emitting layer. This intermediate layer facilitates charge injection and compensates for surface treatment effects, enabling the use of non-oxidizing gases that improve durability while maintaining low drive voltage through proper energy level matching
2Reliability
If non-oxidizing gas such as argon gas is used for surface treatment, then durability is improved, but the work function becomes small requiring higher drive voltage
Solution Approach 1:
The invention optimizes the parameters of the non-oxidizing gas treatment by selecting specific gas types (nitrogen, argon, carbon dioxide, or their mixtures) and controlling treatment conditions. This parameter optimization achieves the right balance between durability improvement and work function modification, preventing excessive work function reduction that would require higher drive voltage
Solution Approach 2:
The hole-injection layer serves as a mediator that compensates for the work function changes induced by non-oxidizing gas treatment. By properly designing this intermediate layer, the system maintains efficient charge injection while benefiting from the improved durability provided by non-oxidizing surface treatment
3Use of energy by moving object
If reducing gas such as hydrogen gas is used for surface treatment, then the work function becomes small, but the hole-injection barrier with respect to organic film becomes large resulting in high drive voltage
Solution Approach 1:
The invention introduces a hole-injection layer as an intermediary that bridges the electrode and the organic light-emitting layer. This intermediate layer has energy levels specifically designed to match both the electrode (after non-oxidizing gas treatment) and the organic film, thereby eliminating the hole-injection barrier that would otherwise result from using reducing gases
Solution Approach 2:
The invention changes the approach to work function modification by using non-oxidizing gases with controlled parameters rather than strong reducing gases. Combined with the hole-injection layer, this parameter change achieves appropriate energy level alignment without creating injection barriers
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 method results in an organic electroluminescence element with suppressed voltage increase during driving and improved durability, with the organic electroluminescence element maintaining luminance for extended periods, suitable for various applications including displays and light sources.
Implementation Method 1
surface treatment using at least one non-oxidizing gas
Implementation Method 2
forming a p-doped hole-injection layer on a surface of the anode
Data Source
AI summary
A method for producing an organic electroluminescence element, the method including subjecting an anode to a surface treatment using at least one non-oxidizing gas, and forming a p-doped hole-injection layer on a surface of the anode subjected to the surface treatment.