Quantum Dot Ligand Gradient for Crosstalk Suppression
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Solution Overview
Problem
Quantum dots with inorganic ligands in display devices experience light emission due to leakage currents, leading to optical crosstalk and deterioration in display quality, such as color mixing and unclear images, due to the inability to effectively suppress light emission from adjacent subpixels.
Innovation Solution
A display device structure with subpixels featuring a light-emitting layer comprising a first region with a higher concentration of inorganic ligands in the central portion and a second region with a lower concentration of inorganic ligands at the edges, preventing light emission from adjacent subpixels through controlled ligand distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If inorganic ligands are used in quantum dots, then light emission efficiency and stability are improved, but light emission due to leakage current occurs causing optical crosstalk
Solution Approach 1:
The patent applies local quality by creating two distinct regions within the light-emitting layer: a first region with high inorganic ligand concentration for efficient light emission, and a second region with low inorganic ligand concentration to suppress leakage current-induced light emission. This spatial differentiation of ligand concentrations allows each region to perform its specific function optimally.
Solution Approach 2:
The light-emitting layer is segmented into multiple regions with different ligand compositions. The first region (central portion) contains quantum dots with high inorganic ligand concentration, while the second region (peripheral portion adjacent to other subpixels) contains quantum dots with low inorganic ligand concentration. This segmentation enables functional differentiation within the same layer.
2Reliability
If inorganic ligands are used in quantum dots, then current injection properties are improved, but light emission from adjacent subpixels occurs due to leakage current
Solution Approach 1:
The patent implements local quality by varying the inorganic ligand concentration spatially within the light-emitting layer. The central region maintains high inorganic ligand content for superior current injection, while the peripheral region near pixel boundaries uses low inorganic ligand content to prevent leakage current from causing unwanted light emission in adjacent subpixels.
Solution Approach 2:
The organic ligands in the second region act as an intermediary that suppresses the harmful effect of leakage current. By reducing inorganic ligand concentration and increasing organic ligand content in the peripheral region, the material properties are modified to prevent charge carrier leakage that would otherwise cause light emission in neighboring subpixels.
3Stability of the object's composition
If inorganic ligands are used in quantum dots, then stability is improved, but optical crosstalk such as color mixing occurs
Solution Approach 1:
The patent applies local quality by creating spatial variation in ligand composition within the light-emitting layer. The first region maintains high inorganic ligand concentration for quantum dot stability, while the second region uses low inorganic ligand concentration to prevent optical crosstalk and color mixing between adjacent subpixels.
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 approach enhances light emission efficiency while suppressing unwanted light emission from adjacent subpixels, thereby improving display quality by reducing optical crosstalk and maintaining high resolution.
Implementation Method 1
a quantum dot containing an inorganic ligand, such as a halogen ligand containing a fluoride, emits light even with a slight leakage current
Data Source
AI summary
In a display device, a light-emitting layer of at least one subpixel includes a first region, and a second region having a number of inorganic ligands contained per unit volume less than a number of the inorganic ligands contained per unit volume in the first region. The first region includes a central portion of the light-emitting layer, and the second region includes at least one end portion among end portions, of the light-emitting layer, adjacent to other adjacent subpixels.