Indium Tin Oxide Powder Crystallinity and Surface Area Control
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Solution Overview
Problem
Existing indium tin oxide (ITO) powders face a trade-off between high crystallinity and large specific surface area, which are necessary for forming transparent and conductive films, as increasing the specific surface area often decreases crystallinity and conductivity.
Innovation Solution
A surface-modified ITO powder with a specific surface area of 40 m²/g or more, a navy blue color tone, and a half-width of the (222) plane peak of 0.6° or less is produced through a method involving coprecipitation of indium tin hydroxide using a tin (Sn2+) compound and indium trichloride, followed by drying and calcining under specific conditions, including a nitrogen atmosphere with alcohol, to enhance crystallinity and conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the primary particle size of ITO powder is decreased to increase specific surface area, then transparency is improved, but crystallinity decreases and conductivity deteriorates
Solution Approach 1:
The patent applies parameter changes by carefully controlling the pH value (4.0-9.3) and temperature (5-80°C) during coprecipitation, as well as the calcination conditions, to achieve optimal crystallinity in fine ITO powder particles while maintaining high specific surface area
Solution Approach 2:
The patent uses coprecipitation as a preliminary action to form ITO powder with controlled particle size and morphology before calcination, ensuring that the desired crystallinity and specific surface area are achieved in the final product
2Illumination intensity
If the primary particle size of ITO powder is decreased to increase specific surface area, then transparency is improved, but conductivity deteriorates
Solution Approach 1:
The patent changes process parameters including pH (4.0-9.3), temperature (5-80°C), and calcination conditions to produce ITO powder with optimal electrical conductivity while maintaining fine particle size for transparency
Solution Approach 2:
The coprecipitation process serves as a preliminary action that pre-forms the ITO powder with controlled particle characteristics, ensuring both transparency and conductivity are achieved after calcination
3Ease of manufacture
If existing ITO powder production methods are used, then manufacturing is simpler, but the resulting powder does not achieve both high specific surface area and high crystallinity
Solution Approach 1:
The patent modifies production parameters by using coprecipitation with controlled pH (4.0-9.3) and temperature (5-80°C), followed by calcination under specific conditions, to achieve precise control over crystallinity and specific surface area while maintaining practical manufacturability
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 resulting ITO powder achieves high transparency and conductivity, with surface resistivity of 20,000 Ω/sq. or less and low Δ transmittance, making it suitable for transparent conductive films and infrared ray shielding applications.
Implementation Method 1
a process of coprecipitating an indium tin hydroxide by using a tin (Sn 2+) compound and indium trichloride
Implementation Method 2
drying and calcining the indium tin hydroxide under specific conditions, including a nitrogen atmosphere with alcohol
Implementation Method 3
the indium tin hydroxide is calcined to produce the indium tin oxide powder in which a surface is modified
Data Source
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AI summary
One aspect of an indium tin oxide powder has a specific surface area of 55 m2/g or more, wherein a color tone is from bright yellow to a color of persimmons or a half-width in the peak of (222) plane is 0.6° or less on an X-ray diffraction chart. Another aspect of the indium tin oxide powder has a modified surface, wherein a specific surface area is 40 m2/g or more, a half-width in the peak of (222) plane is 0.6° or less on an X-ray diffraction chart, and a color tone is navy blue (L is 30 or less in a Lab colorimetric system). A method for producing the indium tin oxide powder includes: coprecipitating an indium tin hydroxide by using a tin (Sn2+) compound under conditions in which pH is 4.0 to 9.3, and a temperature of a liquid is 5°C or higher, wherein the indium tin hydroxide has a color tone from bright yellow to a color of persimmons in a dried powder state; and drying and calcining the indium tin hydroxide.