Full-Color OLED Device with Dual Dopant Emission Layers
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Solution Overview
Problem
Conventional full-color organic electroluminescent devices require high driving voltage and have a limited NTSC ratio, with emission color varying with applied current due to the structure and materials used.
Innovation Solution
A full-color organic electroluminescent device is designed with a specific structure including a first and second emitting layer, each doped with distinct energy gap dopants, and a blocking layer to maintain consistent emission color across varying current densities, reducing driving voltage and enhancing NTSC ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a stacked full-color organic electroluminescent device is fabricated by vertically stacking individual red, blue, and green OLEDs, then a full-color image can be achieved, but the device requires a high driving voltage
Solution Approach 1:
The patent combines multiple emitting layers (red, green, and blue) within a single OLED structure, allowing full-color display without requiring separate stacked devices. This merging approach reduces the overall driving voltage compared to vertically stacked individual OLEDs while maintaining full-color image capability.
Solution Approach 2:
The patent creates a multi-functional emitting layer that can emit multiple colors (red, green, and blue) through different dopants, allowing a single device structure to perform full-color display functions without requiring multiple separate devices or high driving voltages.
2Adaptability or versatility
If conventional full-color organic electroluminescent devices are used, then they can display images, but the emission color varies with applied current and the NTSC ratio is limited
Solution Approach 1:
The patent assigns different dopants with specific energy gaps to different emitting layers (red, green, blue), allowing each layer to maintain its characteristic emission color independently. This local differentiation ensures that the overall emission color remains consistent across varying current densities, improving NTSC ratio.
Solution Approach 2:
The patent carefully selects dopants with specific energy gap parameters (E1, E2, E3) for different emitting layers, ensuring that the emission characteristics remain stable across different operating conditions. By controlling the energy gap parameters of dopants, the device maintains consistent emission color and achieves higher NTSC ratio.
3Stability of the object's composition
If the energy gap E1 of the first dopant is made different from the energy gap E2 of the second dopant, then consistent emission color can be maintained across varying current densities, but the device structure becomes more complex
Solution Approach 1:
The patent divides the emitting layer into multiple distinct layers (first emitting layer with first dopant, second emitting layer with second dopant), each with different energy gaps. This segmentation allows independent optimization of each layer's emission characteristics, maintaining color consistency while managing complexity through systematic layer design.
Solution Approach 2:
The patent uses composite emitting layers containing different dopants with specific energy gaps combined in a structured manner. This composite approach allows the device to maintain consistent emission color across varying current densities while organizing the complexity into a manageable multi-layer composite structure.
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 device achieves reduced driving voltage and improved NTSC ratio by maintaining consistent emission color and increased luminous efficiency across different current densities, outperforming conventional devices.
Implementation Method 1
a first emitting layer and a second emitting layer, sequentially disposed on the first electrode, wherein the first emitting layer has a first dopant doped therein, and the second emitting layer has a second dopant doped therein, and the energy gap E1 of the first dopant is different from the energy gap E2 of the second dopant
Data Source
AI summary
A system for displaying images is provided. The system includes a full-color organic electroluminescent device having an anode. A first emitting layer and a second emitting layer are sequentially disposed on the anode. A cathode is disposed on the second emitting layer. The first and second emitting layers include, respectively, a first dopant and a second dopant, wherein the energy gap of the first dopant is different from that of the second dopant.