OLED Electron Transport Layer Mixing for Lower Drive Voltage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing organic light emitting devices require higher drive voltages and have limited longevity due to the single compound composition of the hole blocking layer and insufficient reduction in the interlayer energy barrier.
Innovation Solution
The organic light emitting device incorporates a sequence of an anode, a light emitting layer, a first electron transport layer, and a second electron transport layer, where both electron transport layers are mixture layers comprising different materials, reducing the interlayer energy barrier and drive voltage, and utilizing hydrocarbon compounds to enhance stability and longevity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the electron transport layer is formed as a mixture layer of a plurality of compounds, then the drive voltage is reduced and color purity is maintained, but the device complexity increases due to multiple materials
Solution Approach 1:
The electron transport layer is formed as a composite layer containing multiple compounds (first compound and second compound) to reduce drive voltage while maintaining color purity. The composite structure allows optimization of electrical properties without sacrificing optical performance
Solution Approach 2:
Different compounds are distributed within the electron transport layer to create local variations in properties. The first compound and second compound are positioned strategically to optimize both charge transport and light emission characteristics in different regions of the layer
2Device complexity
If the hole blocking layer is constituted by a single compound, then the device complexity is reduced, but the drive voltage cannot be sufficiently reduced and longevity is limited
Solution Approach 1:
The hole blocking layer is transformed from a single compound structure to a composite layer containing multiple compounds. This composite structure enables better hole blocking performance and improved electron transport, resulting in reduced drive voltage and enhanced device longevity
3Stability of the object's composition
If the interlayer energy barrier is high, then the material stability is improved, but the drive voltage increases and light emission efficiency decreases
Solution Approach 1:
The energy barrier parameters between layers are optimized by selecting and positioning specific compounds. The first compound and second compound in the electron transport layer are chosen to create appropriate energy level alignments that reduce the interlayer energy barrier, enabling lower drive voltage while maintaining material stability
Solution Approach 2:
The second compound in the electron transport layer acts as an intermediary between the first compound and the light emitting layer. This intermediary material facilitates smooth energy and charge transfer, reducing the energy barrier at the interface while maintaining overall system stability
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
This configuration significantly reduces the drive voltage and improves the longevity of the organic light emitting device by minimizing energy barriers and preventing hole leakage, leading to increased light emission efficiency and durability.
Implementation Method 1
Injection of carriers from these electrodes causes generation of excitons in the light emitting layer. The excitons return to the ground state while releasing energy as light emission.
Data Source
AI summary
An organic light emitting device including, in sequence, an anode, a light emitting layer, a first electron transport layer, a second electron transport layer, and a cathode, wherein the second electron transport layer includes a first material and a second material different from the first material, and the first electron transport layer includes a third material and a fourth material different from the third material.