Top-Emitting OLED Homojunction Structure Reduces Driving Voltage
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Solution Overview
Problem
The existing top-emitting OLED devices have a high driving voltage due to a large number of layers, which creates a significant energy level difference at the interfaces, hindering carrier injection into the light-emitting layer and reducing efficiency.
Innovation Solution
The implementation of a structure with homojunctions in the functional layer, including a hole injection layer, hole transport layer, light emitting layers, electron transport layer, and electron injection layer, with charge generation layers A and B between adjacent light emitting layers, reduces the carrier injection barrier and the number of organic materials, thereby lowering the driving voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a series OLED structure with multiple layers is used to achieve multiple light emitting units, then the device can produce multiple colors and improve current efficiency, but the driving voltage becomes too high due to the large number of layers and significant energy level differences at interfaces
Solution Approach 1:
The patent merges the charge generation layer and transport layer into a single integrated layer structure. This consolidation reduces the total number of interfaces and energy level barriers that carriers must overcome, thereby lowering the driving voltage while preserving the series connection benefits for current efficiency and multi-color emission
Solution Approach 2:
The patent introduces doping with different materials (metal materials, metal compound materials, or organic materials) at specific locations within the charge generation and transport layers. This local modification of material properties creates favorable energy level alignments at critical interfaces without affecting the overall series structure, enabling reduced driving voltage while maintaining high current efficiency
2Reliability
If multiple charge generation layers and transport layers are added to create series OLED structure, then the light emitting units can be connected without mutual interference, but the carrier injection barrier increases and carrier injection efficiency decreases
Solution Approach 1:
By combining the charge generation and transport functions into an integrated layer structure, the patent reduces the number of interfaces carriers must traverse. This merger maintains electrical isolation between light emitting units while minimizing carrier injection barriers, thereby improving carrier injection efficiency without compromising unit independence
Solution Approach 2:
The doped charge generation and transport layers act as intermediary structures that facilitate carrier transfer between light emitting units. The doping creates favorable energy level gradients that mediate carrier injection, reducing injection barriers while maintaining the series connection architecture that ensures unit independence
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 enhances carrier injection efficiency, reduces the driving voltage, and improves the overall performance of the OLED device by minimizing the thickness of layers and the carrier injection barrier.
Implementation Method 1
Organic light emitting diode (OLED) has the characteristics of low energy consumption, low driving voltage, wide color gamut, simple preparation technology, wide angle of view, fast response
Data Source
AI summary
The embodiments of the present invention provide an organic light emitting diode device, display panel and display device. The existing top emitting series OLED device is improved with a structure of homojunctions; the functional layer of the top emitting series OLED device is also improved. The functional layer comprises a hole injection layer, a hole transport layer, a plurality of light emitting layers, an electron transport layer and an electron injection layer sequentially arranged from the anode. A charge generation layer A and a charge generation layer B are arranged between two directly adjacent light emitting layers. A homojunction is applied in each light emitting unit of the top emitting series OLED device, reducing the types of organic materials and the carrier injection barrier, improving the injection of carriers and the efficiency of the device. The driving voltage of the device is thus reduced.