Ag-Ge-S Semiconductor Nanoparticles for Safe Near-Infrared Emission
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Solution Overview
Problem
Existing semiconductor nanoparticles containing toxic elements like Cd, Se, and In pose environmental and health risks, limiting their application in consumer and medical fields due to strict toxic control and health management requirements.
Innovation Solution
Development of semiconductor nanoparticles made from a compound semiconductor primarily consisting of Ag, Ge, and S, with a molar ratio of Ag to Ge between 1.0 and 7.5, and an average particle size of 9 nm or less, which are safer and easier to handle, and can emit light in the near-infrared region, utilizing a core-shell structure with a coating layer to improve emission properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If semiconductor nanoparticles containing toxic elements (Cd, Se, In) are used to achieve light emission properties, then emission performance is improved, but toxic control and health management requirements increase
Solution Approach 1:
The patent changes the compositional parameters of the semiconductor nanoparticles by replacing toxic elements (Cd, Se, In) with non-toxic alternative elements (Ag, Ge, S) in specific molar ratios. This parameter substitution maintains the light emission functionality while eliminating toxicity, directly resolving the contradiction between emission performance and harmful factors
Solution Approach 2:
The patent converts the harmful effect of toxic elements into a benefit by using the replacement elements (Ag, Ge, S) that not only eliminate toxicity but also provide improved light emission properties in the near-infrared region. The non-toxic composition becomes advantageous for biomedical applications where safety is critical
2Illumination intensity
If particle size is reduced to 10 nm or less to exhibit quantum size effect, then light emission wavelength control is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent optimizes multiple parameters simultaneously: the molar ratio of Ag to Ge (1.0 to 7.5), the average particle size (9 nm or less), and the composition ratios. These parameter combinations work together to achieve both precise wavelength control through quantum size effect and manageable manufacturing precision by establishing specific compositional windows that facilitate controlled synthesis
3Illumination intensity
If core-shell structure with coating layer is added to improve emission properties, then emission quantum yield is improved, but device complexity increases
Solution Approach 1:
The patent employs a core-shell composite structure where the core consists of Ag-Ge-S semiconductor nanoparticles and the shell comprises a coating layer. This composite structure improves emission quantum yield by protecting the core and enhancing optical properties, while the simplicity of the two-layer design minimizes the increase in 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 Ag-Ge-S nanoparticles require no strict toxic control, are highly safe, and exhibit improved emission properties, enabling their use in various fields such as bioimaging without harming living tissues and with high light transmittance in the near-infrared range.
Implementation Method 1
atomizing the nanoparticles to a size of 10 nm or less to allow for exhibition of quantum size effect
Implementation Method 2
a coating is formed on a surface of each nanoparticle to deactivate the surface, achieving an emission quantum yield of 10% or more
Implementation Method 3
the peak wavelength of the emission intensity is in the range of 700 nm to 1400 nm and the half width of the peak wavelength is 100 nm or less
Data Source
AI summary
Semiconductor nanoparticles that include a compound semiconductor mainly containing a Ag component, a Ge component, and a S component, wherein a content ratio of the Ag component to the Ge component is 1.0 or more and less than 7.5, in terms of molar ratio, and an average particle size of the semiconductor nanoparticles is 9 nm or less