Quantum Dot Emission Film With Halide Surface Stabilization
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Solution Overview
Problem
Current light emitting devices using quantum dots face challenges in improving performance due to the instability of organic ligands on the surface of quantum dots, leading to reduced conductivity and lifespan.
Innovation Solution
A light emitting device is developed with a quantum dot emission film comprising first and second emission layers made of halide-free quantum dots, where the quantum dots include zinc and selenium, and a charge auxiliary layer of zinc metal oxide nanoparticles, enhancing the interaction between the halide and the quantum dot surface, thereby improving conductivity and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional quantum dots containing cadmium or lead are used, then light emission can be achieved, but the device performance and lifespan are limited due to harmful materials
Solution Approach 1:
The patent removes harmful cadmium and lead from the quantum dot composition entirely, extracting these problematic elements from the material system. The quantum dots are formulated using only zinc, selenium, and halide components, eliminating the harmful factors while maintaining light emission functionality.
Solution Approach 2:
The patent changes the compositional parameters of the quantum dots by specifying precise molar ratios (zinc to selenium ratio) and incorporating halide ions at controlled concentrations (0.01-0.5 ppm). These parameter adjustments optimize the quantum dot properties for improved device performance and lifespan without requiring harmful materials.
2Use of energy by moving object
If halide is incorporated on quantum dot surfaces to improve performance, then electroluminescent efficiency increases, but manufacturing precision requirements increase
Solution Approach 1:
The patent establishes specific parameter ranges for halide incorporation (0.01-0.5 ppm) and zinc-to-selenium molar ratios. By defining these parameters within controlled ranges, the patent achieves improved electroluminescent efficiency while providing clear manufacturing guidelines that balance precision requirements with manufacturability.
Solution Approach 2:
The patent creates a composite quantum dot material system combining zinc, selenium, and halide ions in specific proportions. This composite approach allows the halide to enhance surface properties and electroluminescent efficiency while the zinc and selenium matrix provides structural stability, reducing the stringency of manufacturing precision requirements.
3Productivity
If multiple emission layers with different quantum dots are used, then emission performance improves, but device complexity increases
Solution Approach 1:
The patent divides the emission function into multiple layers, each containing quantum dots with specific compositions (different zinc-to-selenium ratios or halide concentrations). This segmentation allows each layer to optimize for particular emission characteristics, improving overall productivity while maintaining manageable complexity through systematic layer design.
Solution Approach 2:
The patent applies local quality by varying the quantum dot composition parameters (zinc-to-selenium ratio, halide content) in different emission layers. Each layer has locally optimized properties tailored to its specific function, enabling improved emission performance without requiring uniform complexity throughout the entire device structure.
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 results in increased halide ligand substitution rates, significantly higher hole conductivity, and improved electroluminescence efficiency and lifespan of the light emitting device.
Implementation Method 1
semiconductor nanocrystals, also referred to as quantum dots, if activated with photoenergy or electrical energy may emit light in a wavelength corresponding to the particle size of the quantum dots
Implementation Method 2
the first quantum dots and the second quantum dots include a halide on at least a portion of the surface of the quantum dots
Data Source
AI summary
A light emitting device including a first electrode and a second electrode facing each other, a quantum dot emission film disposed between the first electrode and the second electrode, and a charge auxiliary layer disposed between the emission film and the first electrode, between the emission film and the second electrode, or between the emission film and the first electrode and between the emission film and the second electrode, wherein the quantum dot emission film includes a first surface facing the charge auxiliary layer and an opposite second surface. A manufacturing method of making the light emitting device, and a display device including the same.