Organic EL Panel Charge Conversion Layers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional inverted organic EL display panels experience degradation in electron injection performance due to the configuration where the electron transport layer is formed on the electron injection layer, leading to higher energy barriers and reduced current density, making it difficult to maintain luminance and ease of production with commonly used materials.
Innovation Solution
The organic EL display panel is designed with a new inverted structure where charge conversion layers are used to inject electrons into the cathode and holes into the anode, mirroring the conventional configuration, thereby preventing electron injection performance degradation and allowing for the use of easily handleable materials, ensuring consistent luminance and ease of production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the electron transport layer is formed on the electron injection layer in an inverted structure, then the device can be driven by thin-film transistors with inverted polarity, but the electron injection performance degrades due to higher energy barriers
Solution Approach 1:
A charge conversion layer is introduced as an intermediary between the electron injection layer and the electron transport layer. This layer converts electrons from the electron injection layer into holes that can be transported by the electron transport layer, thereby resolving the energy barrier mismatch and maintaining reliable charge transport in the inverted structure
Solution Approach 2:
The invention changes the charge type parameter by converting electrons to holes through the charge conversion layer. This parameter transformation allows the system to overcome the energy barrier issue inherent in the inverted structure while maintaining compatibility with thin-film transistor driving schemes
2Ease of manufacture
If conventional materials are used in the inverted structure, then ease of manufacture is improved, but electron injection performance degradation occurs
Solution Approach 1:
The charge conversion layer serves as a mediator that allows conventional materials to be used while preventing electron injection performance degradation. It transforms the charge carriers in a way that is compatible with conventional material properties, thereby maintaining both ease of manufacture and device reliability
3Device complexity
If the inverted structure is implemented without charge conversion layers, then device complexity is reduced, but luminance consistency cannot be maintained
Solution Approach 1:
The charge conversion layer acts as a necessary intermediary that ensures consistent luminance by properly managing charge carrier conversion and transport. While it adds a layer to the structure, it prevents the more complex problem of luminance inconsistency that would arise from poor charge management in the inverted configuration
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 effectively maintains electron injection performance at levels comparable to conventional organic EL display panels, preventing degradation and simplifying production by using charge conversion layers to manage charge injection, ensuring consistent luminance and ease of production with conventional materials.
Implementation Method 1
Organic electroluminescent elements (hereinafter, also referred to as 'organic EL elements') utilizing electroluminescence of organic materials have drawn attention as display elements used for thin display devices. Organic EL elements emit light when holes injected from the anode and electrons injected from the cathode recombine within a light-emitting layer disposed between these electrodes.
Data Source
AI summary
The organic EL display panel includes: an active matrix substrate including a thin-film transistor; and an organic EL element disposed on the active matrix substrate, the organic EL element including, in the order from the active matrix substrate side, a cathode electrically connected to the thin-film transistor, a first charge conversion layer in contact with the cathode, a first hole injection layer, a first hole transport layer, a first light-emitting layer, a first electron transport layer, a first electron injection layer, a second charge conversion layer, and an anode in contact with the second charge conversion layer, the first charge conversion layer designed to inject electrons into the cathode and emit holes to the first light-emitting layer side, the second charge conversion layer designed to inject holes into the anode and emit electrons to the first light-emitting layer side.