OLED Charge Transport Layer Layout for Low Voltage and Leakage Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing organic light-emitting elements face issues with high driving voltage and unintended light emission, leading to reduced display color gamut due to increased hole mobility in transport layers.
Innovation Solution
The organic light-emitting element incorporates a charge transport layer with specific mobility and thickness relationships, including a first charge transport layer with high mobility, a second layer with intermediate mobility, and a third layer with low mobility, to efficiently transport charges while minimizing leakage to adjacent elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the hole mobility of the hole transport layer is increased to reduce driving voltage, then the driving voltage is reduced, but current is supplied to adjacent organic light-emitting elements causing unintended light emission
Solution Approach 1:
The charge transport layer is divided into three distinct layers with different charge mobilities. The first charge transport layer (closest to the electrode) has high charge mobility to efficiently transport charges and reduce driving voltage. The second and third charge transport layers have progressively lower charge mobilities to act as barriers that prevent charge leakage to adjacent elements, thereby eliminating unintended light emission while maintaining low driving voltage operation.
2Power
If the thickness of the hole transport layer is increased to reduce driving voltage, then the driving voltage is reduced, but current leakage to adjacent elements increases causing unintended light emission
Solution Approach 1:
Each charge transport layer is designed with specific local properties - different charge mobilities and optimized thicknesses. The first layer has high mobility for efficient charge transport, while the second and third layers have lower mobilities to locally suppress charge leakage. This localized differentiation of material properties allows the structure to simultaneously achieve low driving voltage and prevent current leakage to adjacent elements.
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 reduces driving voltage and unintended light emission, maintaining color purity and efficiency in high pixel density displays.
Implementation Method 1
the first charge transport layer, the second charge transport layer, and the third charge transport layer satisfy Formulas (1) and (2) below: μ1 is a charge mobility of the first charge transport layer, μ2 is a charge mobility of the second charge transport layer, and μ3 is a charge mobility of the third charge transport layer
Data Source
AI summary
The present disclosure provides an organic light-emitting element including a first electrode, an organic compound layer, and a second electrode, wherein the organic compound layer includes a charge transport layer, and the charge transport layer includes a first charge transport layer, a second charge transport layer, and a third charge transport layer in this order, and the first charge transport layer, the second charge transport layer, and the third charge transport layer satisfy Formulas (1) and (2) below:μ1>μ2>μ3(1)d1+d2<d3(2)in Formula (1), μl, μ2, and μ3 are charge mobilities of the first to third charge transport layers, andin Formula (2), d1, d2, and d3 are layer thicknesses of the first to third charge transport layers.