Light-emitting element leakage current control
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Solution Overview
Problem
Existing electroluminescent elements, such as QLED and OLED, suffer from low luminous efficiency due to unaddressed leakage current and degradation of hole transport materials during patterning processes.
Innovation Solution
A light-emitting element configuration with a functional layer having a porosity of 9% to 60% and strategically positioned pores above the boundary line between electrodes, combined with a rapid temperature increase process to form the functional layer, which reduces leakage current and enhances luminous efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the hole injection layer and hole transport layer are patterned for each pixel, then the leakage current can be guided, but the etching step, rinsing step, and resist layer for patterning degrade the performance of the hole transport material
Solution Approach 1:
The functional layer is divided into pixel regions and non-pixel regions, with pores selectively formed only in the non-pixel regions adjacent to pixel electrodes. This segmentation allows leakage current to be guided away from pixel regions without requiring patterning of the entire functional layer, thus avoiding degradation of hole transport material in pixel regions.
Solution Approach 2:
The non-pixel regions with pores act as intermediary zones that intercept and guide leakage current away from pixel regions. These intermediary regions with controlled porosity (9%-60%) serve as a buffer zone that manages current flow without requiring complex patterning steps on the functional layer itself.
2Reliability
If the functional layer is patterned for each pixel, then leakage current can be controlled, but the device complexity and manufacturing steps increase
Solution Approach 1:
Instead of patterning the entire functional layer, only specific non-pixel regions are selected for pore formation. This selective segmentation simplifies the manufacturing process by reducing the scope of patterning operations while still achieving effective leakage current control at pixel boundaries.
Solution Approach 2:
The functional layer exhibits different properties in different regions: pixel regions maintain intact hole transport material for efficient charge transport, while non-pixel regions have controlled porosity for leakage current management. This local differentiation achieves both performance and reliability without complex global patterning.
3Reliability
If pores are formed in the functional layer above the boundary line, then leakage current is reduced, but the manufacturing precision required for pore positioning increases
Solution Approach 1:
Pores are selectively formed only in non-pixel regions adjacent to pixel electrodes, maintaining high hole transport material quality in pixel regions. This localized approach to pore formation achieves leakage current reduction without requiring precise pore positioning across the entire functional layer, as pores are only needed at specific boundary locations.
Solution Approach 2:
The non-pixel regions are identified and prepared for pore formation before the pixel regions undergo hole transport material deposition. This preliminary action ensures that leakage current pathways are established in advance, simplifying subsequent manufacturing steps and reducing positioning requirements.
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 solution significantly improves luminous efficiency by reducing leakage current and eliminating the need for complex patterning steps, thereby increasing the effectiveness of light emission and reducing manufacturing costs.
Implementation Method 1
the functional layer has a pore above the vicinity region of the boundary line... significantly improves luminous efficiency by reducing leakage current
Implementation Method 2
a step of rapidly elevating temperature of the coating film
Data Source
AI summary
An electron transport layer provided between a cathode and a light-emitting layer has pores above a vicinity region of a boundary line between a top face of an anode and a side face of a bank, the vicinity region including the boundary line.