Quantum Dot Shell Growth for Higher LED Luminous Efficiency
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Solution Overview
Problem
There is a need to improve the luminous efficiency in light-emitting devices that incorporate quantum dot layers.
Innovation Solution
A method for manufacturing a light-emitting device involving the formation of a quantum dot layer with a core/shell structure, where quantum dots are coated with a first shell and a second shell through controlled heating processes, and the use of a ligand to enhance the stability and density of the quantum dots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a quantum dot layer is formed with a core/shell structure using ligands and solvents, then the quantum dots can be stabilized and coated, but the luminous efficiency remains insufficient
Solution Approach 1:
The patent applies parameter changes by controlling the atmospheric temperature through staged heating processes. The temperature is raised to a first temperature (higher than the melting point of the ligand and boiling point of the solvent) to remove ligands and solvents, then raised to a second temperature (higher than the first) to enable epitaxial growth of the shell. This precise temperature parameter control transforms the quantum dot structure to achieve both stability and high luminous efficiency.
Solution Approach 2:
The patent utilizes phase transitions of the ligand and solvent during the heating process. The ligand melts and the solvent evaporates at the first temperature, removing organic components that reduce luminous efficiency. This phase transition approach cleanly eliminates energy-loss sources while preserving the quantum dot core structure.
Solution Approach 3:
The patent extracts harmful organic components (ligands and solvents) from the quantum dot structure through thermal processing. By removing these components at the first temperature stage, the patent eliminates sources of energy loss and improves luminous efficiency while maintaining quantum dot stability through subsequent shell formation.
2Loss of energy
If multiple heating stages are applied to form core/shell quantum dots, then the luminous efficiency improves, but the manufacturing process complexity increases
Solution Approach 1:
The patent merges multiple functions into a single continuous heating process. The first heating stage simultaneously accomplishes ligand removal and solvent evaporation, while the second heating stage performs epitaxial shell growth. This combined approach achieves complex structural transformation without requiring separate processing steps, thereby improving luminous efficiency while managing manufacturing complexity.
Solution Approach 2:
The patent maintains continuous useful action through an uninterrupted heating process that progresses from the first temperature stage to the second temperature stage. This continuous thermal processing eliminates idle time between steps and ensures that the quantum dots undergo systematic transformation, improving efficiency while keeping the manufacturing process streamlined.
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 method enhances the luminous efficiency and reliability of the light-emitting device by improving the density and stability of the quantum dots, reducing electron exudation, and minimizing damage from moisture infiltration.
Implementation Method 1
the first inorganic precursor epitaxially grows around the first shell and a second shell coating the first shell is formed
Implementation Method 2
a ligand coordinating with each of the plurality of quantum dots
Implementation Method 3
the first temperature being a higher temperature of a melting point of the ligand and a boiling point of the first solvent
Data Source
AI summary
A method for manufacturing a light-emitting device a first solution including a first solvent, quantum dots, a ligand, and a first inorganic precursor, the quantum dots each including a core and a first shell performing first heating of raising to a first temperature or higher, the first temperature being a higher temperature of a melting point of the ligand and a boiling point of the first solvent, and performing second heating of raising to a second temperature, the second temperature being higher than the first temperature and being a temperature at which the first inorganic precursor epitaxially grows and a second shell coating the first shell is formed to form a plurality of first quantum dots, and wherein a plurality of second quantum dots each including, in a core, the same material as a material of the second shells are also formed.