Cadmium-Free Quantum Dots With Condensed Polycyclic Ligands
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Solution Overview
Problem
There is a need for quantum dots that emit blue light with a maximum emission wavelength of 490 nm or less, have high luminescence quantum efficiency (PLQY), and do not contain the toxic element cadmium, for use in high-quality optical members and electronic apparatuses.
Innovation Solution
A quantum dot comprising a nanomaterial with a core and shell structure, where the surface is coated with a first ligand containing a condensed polycyclic group, and a method involving the exchange or mixing of ligands to enhance properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If quantum dots are used to emit blue light with high luminescence quantum efficiency, then the emission wavelength can be controlled to 490 nm or less, but the use of cadmium-containing quantum dots introduces toxic elements
Solution Approach 1:
The patent changes the compositional parameters of the quantum dot core by using zinc oxide instead of cadmium-based materials, while adjusting the shell composition and thickness parameters to maintain high luminescence quantum efficiency and blue light emission wavelength of 490 nm or less
Solution Approach 2:
The patent employs a composite core-shell structure where a zinc oxide core is coated with a shell containing zinc oxide and other semiconductor materials, creating a composite quantum dot that eliminates toxic cadmium while maintaining optimal optical properties for blue light emission
2Adaptability or versatility
If quantum dots are used as light-emitting materials in optical members, then various optical functions can be achieved, but the device complexity increases due to the need for precise control of emission wavelength and efficiency
Solution Approach 1:
The patent designs a universal quantum dot platform with a zinc oxide core and configurable shell structure that can be adapted for multiple optical functions including blue light emission, color conversion, and photo-conversion, reducing device complexity by using a single core design for various applications
Solution Approach 2:
The patent applies local quality modification by creating a core-shell structure where the core provides the fundamental emission properties while the shell with specific thickness and composition locally enhances luminescence quantum efficiency and stabilizes emission wavelength, allowing precise control without increasing overall device complexity
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 provides quantum dots with improved luminescence efficiency and absence of cadmium, suitable for optical members and electronic apparatuses.
Implementation Method 1
quantum dots may be used as an emitter (e.g., a light emitting material)... quantum dots may act as emitters by being included in an emission layer
Implementation Method 2
the first ligand includes a condensed polycyclic group in which two or more rings are condensed... a quantum dot includes: a nanomaterial and a first ligand on a surface of the nanomaterial
Data Source
AI summary
A quantum dot, a method of manufacturing the quantum dot, a composition including the quantum dot, an optical member including the quantum dot, and an electronic apparatus including the quantum dot are disclosed. The quantum dot includes: a nanomaterial; and a first ligand arranged on a surface of the nanomaterial, wherein the nanomaterial includes a core and a shell that covers at least a part of the core, wherein the first ligand includes a condensed polycyclic group in which two or more rings are condensed.