Hexaboride Particle Shape Control for Near-Infrared Absorption
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Solution Overview
Problem
Hexaboride fine particles used in solar radiation shielding materials do not sufficiently absorb light in the near-infrared region, particularly around 1000 nm, leading to insufficient shielding performance when high visible light transmittance is required, and mixing different types of light-absorbing particles complicates the dispersion process and quality control.
Innovation Solution
Controlling the shape of hexaboride fine particles by adjusting their aspect ratio to 1.5 or more and less than 4.0, and 4.0 or more and less than 20.0, and mixing them at specific ratios to create an assembly that effectively absorbs near-infrared light while maintaining visible light transmittance, using a bead mill with appropriate shear force and dispersant to produce the desired particle shape and distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the concentration of hexaboride fine particles is increased to absorb light in the vicinity of 1000 nm wavelength, then near-infrared absorption is improved, but visible light absorption increases and transparency deteriorates
Solution Approach 1:
The invention changes the shape parameter of hexaboride fine particles from spherical to non-spherical with specific aspect ratios (1.05-2.50). This parameter change in particle morphology alters the light absorption characteristics, enabling strong near-infrared absorption at 1000 nm wavelength while maintaining high visible light transmittance, thus resolving the contradiction between near-infrared absorption and visible light transparency
Solution Approach 2:
The invention uses composite hexaboride fine particles with specific aspect ratios combined in defined proportions (first particles with aspect ratio 1.05-1.80 and second particles with aspect ratio 1.80-2.50). This composite approach creates synergistic effects where different shaped particles contribute to broadening the absorption spectrum in the near-infrared region while collectively maintaining transparency in the visible region
2Loss of energy
If different types of light-absorbing particles are mixed to improve solar radiation shielding, then shielding performance is improved, but dispersion process complexity and quality control difficulty increase
Solution Approach 1:
The invention uses particles of the same material type (hexaboride) with different aspect ratios, maintaining material homogeneity. This approach achieves effective solar radiation shielding through shape-controlled optical properties while avoiding the dispersion and compatibility issues that arise from mixing different material types, thus reducing process complexity and quality control difficulty
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 achieves wide absorption in the near-infrared region, enhancing the solar radiation shielding properties of hexaboride fine particle assemblies while maintaining transparency and stability, effectively addressing the limitations of existing hexaboride particle dispersions.
Implementation Method 1
the hexaboride fine particles have a strong capability of absorbing near infrared while maintaining high transparency
Implementation Method 2
using a bead mill with appropriate shear force and dispersant to produce the desired particle shape and distribution
Data Source
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AI summary
There is provided new transparent near infrared absorptive fine particles having a wide range of near infrared absorption, which are an assembly of hexaboride fine particles, wherein when a particle shape of the number of particles contained in the assembly is approximately regarded as a spheroid body, there are 20 % or more and less than 80 % of particles having an aspect ratio [(long axis length)/(short axis length)] of 1.5 or more and less than 5.0, and there are 20 % or more and less than 80 % of particles having an aspect ratio of 5.0 or more and less than 20.0.