Core-Shell Quantum Dots with Mesoporous Silica Shell
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Solution Overview
Problem
The instability of quantum dots due to interaction with oxygen and water in the air leads to a decrease in fluorescence intensity over time, limiting their long-term use in devices, as existing stabilization methods like polymer and silicon dioxide coatings are insufficient in fully isolating the quantum dots from the environment.
Innovation Solution
A core-shell type quantum dot structure is developed, featuring a quantum dot core coated with a light-transmitting inorganic mesoporous material layer and filled with a filler different from the mesoporous material, which is chemically bonded within the mesopores, and optionally further coated with a light-transmitting metal oxide passivation layer to enhance stability and optical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polymer coating is applied to the quantum dot surface, then the quantum dot stability is improved to some extent, but the polymer material has an open structure that allows direct contact with external water and oxygen, resulting in insufficient isolation
Solution Approach 1:
The patent applies porous materials by using a mesoporous silicon dioxide shell with controlled pore sizes (2-50 nm) that are filled with inert gas or vacuum, creating a physical barrier that prevents water and oxygen from reaching the quantum dot surface while maintaining structural integrity and optical properties
Solution Approach 2:
The patent combines multiple materials in a composite structure: the quantum dot core is coated with a mesoporous silicon dioxide shell, and the pores are filled with inert gas or vacuum, creating a composite system that leverages the protective properties of both the shell and the filled pores to achieve superior isolation from environmental factors
2Reliability
If a silicon dioxide shell with mesoporous structure is used, then the isolation from moisture and oxygen is partially improved, but external air and moisture can still interact with surface ligands through mesoporous channels during long-term use
Solution Approach 1:
The patent utilizes porous materials by employing a mesoporous silicon dioxide shell with precisely controlled pore dimensions (2-50 nm) that are subsequently filled with inert gas or vacuum, creating a permanent physical barrier that blocks the diffusion pathways for water and oxygen molecules, thereby preventing their interaction with the quantum dot surface ligands even during prolonged exposure
Solution Approach 2:
The patent creates an inert environment by filling the mesoporous channels with inert gas or vacuum, which eliminates the presence of reactive oxygen and water molecules within the pore structure, thereby preventing oxidation and hydrolysis reactions at the quantum dot surface during long-term use
3Adaptability or versatility
If the quantum dot surface ligands are exposed to the external environment, then the quantum dot can interact with the environment, but the ligand shedding or oxidation occurs, causing fluorescence intensity to decrease or quench
Solution Approach 1:
The patent applies porous materials by using a mesoporous silicon dioxide shell with controlled pore sizes that are filled with inert gas or vacuum, creating a physical barrier that prevents water and oxygen from reaching the quantum dot surface and causing ligand oxidation or shedding, thereby maintaining fluorescence intensity stability
Solution Approach 2:
The patent introduces an intermediary substance (inert gas or vacuum) within the mesoporous structure that acts as a mediator between the external environment and the quantum dot surface, blocking the harmful interactions while allowing the quantum dot to maintain its optical properties
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 significantly improves the optical and chemical stability of quantum dots by isolating them from the external environment, maintaining fluorescence intensity over time and allowing for adjustable optical performance through the selection of fillers, thereby extending their service life and enhancing their application in various devices.
Implementation Method 1
a light-transmitting inorganic mesoporous material layer on a surface of the quantum dot core
Implementation Method 2
a filler different from the inorganic mesoporous material in mesopores of the light-transmitting inorganic mesoporous material layer
Implementation Method 3
Semiconductor quantum dot (commonly referred to as semiconductor nanocrystal or quantum dot for short) is an important inorganic nano fluorescent material
Implementation Method 4
the filler is fixed in the mesopores by chemical bonding
Data Source
AI summary
The present disclosure relates to a core-shell type quantum dot, comprising a quantum dot core, a light-transmitting inorganic mesoporous material layer on a surface of the quantum dot core, and a filler different from the inorganic mesoporous material in mesopores of the light-transmitting inorganic mesoporous material layer. The present disclosure also relates to the preparation and use of the core-shell type quantum dot core. The quantum dot core is coated with the light-transmitting inorganic mesoporous material and the mesopores of the inorganic mesoporous material are filled with the filler different from the inorganic mesoporous material, and the core-shell type quantum dots thus obtained not only have improved optical stability and chemical stability, but also have adjustable optical properties.