InP Nanoparticles Core Shell Structure Weather Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Semiconductor nanoparticles face a tradeoff between high quantum efficiency and weather resistance, as increasing the shell thickness to improve absorptance of excitation light decreases quantum efficiency, while also increasing film thickness and altering emission characteristics.
Innovation Solution
InP-based semiconductor nanoparticles with a core/shell structure comprising In, P, Zn, Se, S, and a halogen, where the molar ratios of these elements are optimized to achieve a thin shell that enhances quantum efficiency and weather resistance, with a halogen added to improve quantum efficiency and minimize aggregation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the shell thickness is increased to improve weather resistance and protect semiconductor nanoparticles from external influences, then weather resistance is improved, but quantum efficiency decreases and film thickness increases
Solution Approach 1:
The patent applies parameter changes by optimizing the shell thickness to a specific range (0.1 nm to 2.0 nm) and controlling the molar ratios of shell materials (ZnS: 0.1-5.0 relative to InP, ZnSe: 0.1-5.0 relative to InP) to achieve both high weather resistance and high quantum efficiency. This resolves the contradiction by finding the optimal parameter range where protective function is sufficient without excessively reducing light absorption.
Solution Approach 2:
The patent uses composite materials by combining InP core with ZnS and ZnSe shell materials to create a core/shell structure. The composite structure allows the InP core to maintain high quantum efficiency while the ZnS/ZnSe shell provides weather resistance and protection, resolving the contradiction through material composition optimization.
2Quantity of substance
If the shell thickness is increased to improve absorptance of excitation light, then absorptance is improved, but quantum efficiency decreases
Solution Approach 1:
The patent resolves this contradiction by precisely controlling shell thickness parameters (0.1 nm to 2.0 nm) and shell material composition ratios, achieving optimal balance where the shell provides sufficient absorptance enhancement without becoming thick enough to reduce quantum efficiency.
Solution Approach 2:
The patent applies local quality by creating a core/shell structure where the InP core maintains high quantum efficiency for light emission while the ZnS/ZnSe shell provides enhanced absorptance for excitation light. Each region has optimized properties for its specific function, resolving the contradiction through spatial differentiation of material 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
The optimized composition and structure of the semiconductor nanoparticles result in high quantum efficiency and improved weather resistance, maintaining 90% or more quantum efficiency even after heat treatment, while reducing film thickness and stabilizing emission characteristics.
Implementation Method 1
Since excitons in semiconductor nanoparticles formed by photoexcitation, a charge injection method or the like emit photons with an energy corresponding to a band gap due to recombination
Implementation Method 2
Semiconductor nanoparticles that are microscopic to the extent that they exhibit a quantum confinement effect have a band gap that depends on the particle diameter
Implementation Method 3
emit photons with an energy corresponding to a band gap due to recombination
Implementation Method 4
ZnS, which is widely used as a shell for InP-based semiconductor nanoparticles, has a large band gap, and absorbs hardly any blue light. Similarly, ZnSe, which is widely used as a shell for InP-based semiconductor nanoparticles, also has a large band gap, and thus it absorbs hardly blue light. However, since ZnSe has a narrower band gap than ZnS, even if the shell is thickened, the decrease in the absorptance of excitation light can be reduced to some extent.
Data Source
Figure 1A~1C
Figure 1D~1E
Figure 2
AI summary
An object of the present invention is to provide semiconductor nanoparticles having high quantum efficiency and also high weather resistance. Semiconductor nanoparticles according to an embodiment of the present invention are semiconductor nanoparticles including at least, In, P, Zn, Se, S and a halogen, wherein the contents of P, Zn, Se, S and the halogen, in terms of molar ratio with respect to In, are as follows: 0.05 to 0.95 for P, 0.50 to 15.00 for Zn, 0.50 to 5.00 for Se, 0.10 to 15.00 for S, and 0.10 to 1.50 for the halogen.