Cu-Added I-III-VI Quantum Dots for Narrow Band-Edge Emission
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Solution Overview
Problem
Existing I-III-VI based quantum dots exhibit broad full width at half maximum and defect state emission, making them unsuitable for display materials, and there is a need for eco-friendly alternatives with narrow full width and band-edge emission.
Innovation Solution
The development of I-III-VI based quantum dots with a core containing Cu, Group 13 elements, and Group 16 elements, and a shell structure formed through cation exchange, resulting in band-edge emission in the visible and infrared regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If I-III-VI based quantum dots are used as display materials, then they offer eco-friendly composition, but they exhibit broad full width at half maximum and defect state emission which makes them unsuitable for display applications
Solution Approach 1:
The patent changes the compositional parameters of I-III-VI quantum dots by incorporating specific ratios of Cu, In, Ga, S, and Se elements. By adjusting these compositional parameters and controlling particle size within 2-5 nm, the quantum dots achieve narrow full width at half maximum (≤60 nm) and dominant band-edge emission while maintaining eco-friendly composition without Cd or Pb
Solution Approach 2:
The patent creates composite quantum dot structures by combining multiple elements (Cu, In, Ga, S, Se) in specific ratios. The composite nature of these multi-element I-III-VI quantum dots enables simultaneous achievement of narrow emission width, high quantum efficiency, and eco-friendly composition, resolving the contradiction between environmental friendliness and optical performance
2Object-affected harmful factors
If I-III-VI based quantum dots are used as display materials, then they offer eco-friendly composition, but they exhibit defect state emission instead of band-edge emission
Solution Approach 1:
The patent achieves reliable band-edge emission by precisely controlling compositional parameters (ratios of Cu, In, Ga, S, Se) and particle size parameters (2-5 nm). These parameter optimizations eliminate defect states and enable dominant band-edge emission, making the quantum dots reliable for display applications while maintaining eco-friendly composition
Solution Approach 2:
The patent applies local quality control by optimizing specific regions of the quantum dot structure and composition. By carefully controlling the local stoichiometry and atomic arrangement of Cu, In, Ga, S, and Se elements, the quantum dots achieve uniform band-edge emission characteristics throughout the material, ensuring high reliability for display use
3Use of energy by moving object
If red InP quantum dots are used to achieve sufficient light absorption, then larger particle size is needed, but this increases absorbance due to low blue light conversion efficiency
Solution Approach 1:
The patent changes the material composition parameters from traditional InP to I-III-VI (Cu, In, Ga, S, Se) quantum dots. By adjusting the compositional ratios and particle size (2-5 nm), these quantum dots achieve both sufficient light absorption and high blue light conversion efficiency, eliminating the energy loss problem associated with larger particle size InP quantum dots
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 quantum dots achieve narrow full width at half maximum and dominant band-edge emission, suitable for display applications, with enhanced emission efficiency and quantum efficiency.
Implementation Method 1
The Cu is incorporated into the core by cation exchange reaction with the Group 11 element
Data Source
AI summary
There are provided I-III-VI based quantum dots added with Cu with narrow full width at half maximum for use as display materials and a method for fabricating the same. The quantum dots according to the present disclosure include a core including Cu, Group 13 element and Group 16 element; and a shell on the core, wherein the core optionally further includes Group 11 element other than the Cu, and wherein the quantum dots exhibit band-edge emission in a visible light region and an infrared region.