Hole Transport Layer Ionization Potential Alignment for Luminous Efficiency
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Solution Overview
Problem
The existing light-emitting elements with inorganic hole transport layers suffer from poor hole transport efficiency due to the mismatch in ionization potential between the hole transport layer and the quantum dot light-emitting layer, leading to unbalanced electron and hole transport and reduced luminous efficiency.
Innovation Solution
A light-emitting element is designed with a hole transport layer containing a metal oxide of (NiO)1-x(LaNiO3)x or (CuyO)1-x(LaNiO3)x, where 0<x≤1, to align the ionization potential and improve hole transport efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a known inorganic material (NiO) is used as the hole transport layer, then the material stability and reliability are improved, but the hole transport efficiency deteriorates due to ionization potential mismatch
Solution Approach 1:
The invention changes the ionization potential parameter of the hole transport layer by replacing pure NiO with a metal oxide having ionization potential of 5.8 eV or higher. This parameter change resolves the contradiction by maintaining material stability while achieving better energy level alignment with quantum dots (ionization potential 6-7 eV), thereby improving hole transport efficiency.
Solution Approach 2:
The invention uses composite materials by combining metal oxides with appropriate ionization potentials to create a hole transport layer that achieves both stability and efficient hole transport. The composite approach allows optimization of both reliability and productivity by selecting materials that satisfy both criteria simultaneously.
2Ease of operation
If the hole transport layer uses inorganic material with lower ionization potential, then the ease of hole injection is improved, but the balance with electron transport deteriorates leading to reduced luminous efficiency
Solution Approach 1:
The invention optimizes the ionization potential parameter to 5.8 eV or higher, which strikes the right balance between ease of hole injection and maintenance of luminous efficiency. This parameter selection ensures that holes can be efficiently injected while maintaining balance with electron transport to the light-emitting layer.
Solution Approach 2:
The invention achieves equipotentiality by matching the ionization potential of the hole transport layer (5.8 eV or higher) with that of the quantum dot light-emitting layer (6-7 eV). This energy level alignment creates balanced transport conditions for both holes and electrons, improving overall luminous efficiency while maintaining ease of operation.
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 balance between hole and electron transport, resulting in improved luminous efficiency and reliability of the light-emitting element.
Implementation Method 1
Incorporating a hole transport layer made of a metal oxide composite, such as (NiO)1-x(LaNiO3)x or (CuyO)1-x(LaNiO3)x, where 0<x≤1, to adjust the ionization potential and improve hole injection efficiency
Data Source
AI summary
A light-emitting element includes a hole transport layer between a light-emitting layer and an anode, the hole transport layer containing either a metal oxide of (NiO)1-x(LaNiO3)x (composition formula 1) or (CuyO)1-x(LaNiO3)x (composition formula 2), where 0<x≤1 and 1≤y≤2.