Tandem OLED Vertical Stacking Crosstalk Reduction
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Solution Overview
Problem
Conventional tandem organic electroluminescent devices face issues with crosstalk between pixels due to carrier migration within electrodes, poor reproducibility of thin intermediate electrodes, and high driving voltage caused by unstable charge generating layers, which hinder efficient and cost-effective mass production.
Innovation Solution
A tandem organic electroluminescent device with a substrate featuring a rib with chambered corners and a protrusion in the display region, where organic light-emitting diodes are vertically stacked, and the bottom electrode of the bottommost diode is connected to a pixel thin film transistor, with a common electrode connecting the top electrodes of adjacent diodes, preventing crosstalk and improving carrier transport.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a thin intermediate electrode is used to reduce crosstalk, then crosstalk between pixels is reduced, but the reproducibility of the electrode becomes poor
Solution Approach 1:
The intermediate electrode is divided into multiple segments (first intermediate electrode layer and second intermediate electrode layer) separated by an organic electroluminescent layer. This segmentation allows each layer to be optimized independently - the first layer can be thin for low crosstalk while the second layer provides better reproducibility and electrical connection stability.
2Reliability
If a charge generating layer is used to improve carrier transport, then carrier transport ability is enhanced, but the stability of the connection layer deteriorates due to high operating voltage
Solution Approach 1:
An organic electroluminescent layer is introduced as an intermediary between the first and second intermediate electrode layers. This organic layer acts as a mediator that facilitates carrier transport while protecting the electrode structure from the destabilizing effects of high operating voltage, thereby maintaining connection layer stability.
3Device complexity
If a conventional tandem structure with direct electrode contact is used, then device complexity is reduced, but crosstalk between adjacent pixels occurs
Solution Approach 1:
The patent introduces a vertical dimension to the electrode structure by stacking multiple electrode layers separated by organic electroluminescent layers. This vertical arrangement (first intermediate electrode layer below, second intermediate electrode layer above) creates spatial separation that prevents lateral carrier migration and crosstalk while maintaining electrical connection functionality.
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 the stability and efficiency of carrier transport, reduces crosstalk, and allows for more reliable and cost-effective mass production by eliminating the need for toxic materials and complex patterning processes.
Implementation Method 1
organic electroluminescent layer
Implementation Method 2
carrier diffusion effect
Implementation Method 3
carrier transport ability
Data Source
AI summary
A tandem organic electroluminescent device. The tandem organic electroluminescent device comprises a substrate having a pixel thin film transistor. A rib with chambered corners is formed on the substrate, surrounding a display region. A protrusion is formed in the display region. A plurality of organic light emitting diodes is stacked vertically in the display region, covering the protrusion, wherein each organic light emitting diode comprises a top electrode, an organic electroluminescent layer, and a bottom electrode. The bottom electrode of the bottommost organic light emitting diode is electrically connected to the pixel thin film transistor. A common electrode electrically connected to the top electrode of the topmost organic light emitting diode directly over the protrusion.