Quantum Dot Emitting Layers With Gradient Ligands for Carrier Injection
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Solution Overview
Problem
Existing quantum dot light emitting devices face challenges in carrier transmission and efficiency due to large energy level barriers between layers, leading to suboptimal performance.
Innovation Solution
The device incorporates sub-function layers with gradiently changing surface energies and ligands to match energy levels, forming stepped barriers that enhance carrier transmission and balance, using materials like magnesium zinc oxide nanoparticles and quantum dots with specific ligands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If traditional single-layer light emitting function layers are used, then device structure is simple, but carrier transmission is poor due to large energy level barriers
Solution Approach 1:
The light emitting function layer is divided into multiple sub-function layers (electron transport sub-layer, light emitting sub-layer, hole transport sub-layer) with gradient surface energies. This segmentation creates stepped energy level barriers that facilitate carrier transmission while maintaining manageable structural complexity through systematic design.
Solution Approach 2:
Each sub-function layer is assigned specific ligands with tailored surface energies to create local energy level optimizations. The gradient distribution of ligand surface energies (from high to low across the layers) enables localized control over carrier transport properties, improving overall device performance.
2Reliability
If sub-function layers with gradient surface energy ligands are introduced, then carrier transmission is improved, but device complexity increases
Solution Approach 1:
The surface energy parameter of ligands is systematically varied across sub-function layers to create gradient energy levels. By controlling ligand composition (e.g., carboxylic acid, phosphonic acid, amine groups) and their surface energy characteristics, the patent optimizes carrier transmission without requiring excessive structural complexity.
Solution Approach 2:
The patent employs composite material strategies by combining quantum dots with different ligand types (organic carboxylic acids, inorganic phosphonic acids, amine ligands) to create sub-function layers with tailored properties. This composite approach enables fine-tuned energy level alignment while maintaining material versatility.
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 design improves electron and hole injection capabilities, resulting in enhanced device efficiency and performance by aligning energy levels for optimal carrier flow.
Implementation Method 1
surface energy of the ligands corresponding to the sub-function layers gradiently changes in a transmission direction of carriers in the sub-function layers, so that energy levels of the sub-function layers gradiently change
Implementation Method 2
energy levels of the sub-function layers gradiently change
Implementation Method 3
Quantum dot light emitting diodes (QLED) have the advantages of high luminous intensity, good monochromaticity
Implementation Method 4
Quantum dot light emitting diodes (QLED)
Data Source
AI summary
Disclosed are a quantum dot light emitting device, a preparation method thereof and a display apparatus. In embodiments of the present disclosure, at least one of one or more light emitting function layers is disposed to include at least two sub-function layers, each sub-function layer includes ligands, and surface energy of the ligands corresponding to the sub-function layers gradiently changes in a transmission direction of carriers in the sub-function layers, so that energy levels of the sub-function layers gradiently change. In this way, the energy levels of the sub-function layers can be matched with energy levels of the adjacent light emitting function layers.