Carbon Nanotube Yarn Emitters With Smooth Surface Electron Emission
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Solution Overview
Problem
Conventional methods for fabricating horizontally aligned carbon nanotube field electron emitters are inefficient and costly, with protruding tip ends reducing electron emission efficiency, and existing methods require complex processes with organic or inorganic binders to achieve a smooth surface.
Innovation Solution
A method involving the densification of carbon nanotube yarn through rotation and heat treatment using organic solvents, eliminating the need for binders, to create a smooth surface with enhanced bonding and uniform electron emission from the surface of the yarn.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If carbon nanotube strands are plied together to form yarn, then the yarn structure is formed, but the tip ends protrude from the surface reducing field electron emission efficiency
Solution Approach 1:
The patent applies heat treatment to change the physical state and arrangement of carbon nanotube strands, causing them to densify and retract from the surface. This thermal parameter change transforms the protruding tip ends into a smooth surface configuration, resolving the contradiction between yarn formation and surface smoothness.
Solution Approach 2:
The patent replaces mechanical binding methods with heat treatment-induced densification. Instead of using external binders or mechanical compression, the thermal energy directly causes the nanotube strands to reorganize and densify, achieving surface smoothing through thermal-mechanical self-organization.
2Manufacturing precision
If binders or polymer pastes are added to flatten the yarn surface, then surface smoothness is improved, but the process becomes complicated and cost increases
Solution Approach 1:
The patent enables the carbon nanotube yarn to self-densify and self-smooth through heat treatment without requiring external binders or additional processing equipment. The thermal treatment causes the nanotube strands to automatically reorganize and densify, making the system self-sufficient and eliminating complex fabrication steps.
Solution Approach 2:
The patent extracts and eliminates the need for binders and polymer pastes from the fabrication process. By using heat treatment-induced densification, the harmful and complicating elements (binders) are completely removed, achieving surface smoothness through a cleaner, simpler method.
3Ease of manufacture
If carbon nanotube strands are plied together, then yarn is formed, but homogeneous and reproducible fabrication is difficult without binders
Solution Approach 1:
The patent uses heat treatment as a controlled parameter change to achieve uniform densification throughout the yarn structure. This thermal parameter application ensures homogeneous reorganization of nanotube strands, producing reproducible fabrication results without requiring binders for structural stability.
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 produces carbon nanotube yarns with improved homogeneity, reproducibility, stability, and economic feasibility, enabling efficient and reliable field electron emission for various devices, including light emitting sources, with uniform electron emission from the surface.
Implementation Method 1
an organic solvent selected from methanol, ethanol, acetone, dichloroethane, chloroform, ethylene glycol, dichlorobenzene, and dimethylformamide is used for plying thin carbon nanotube strands
Implementation Method 2
densification during rotation of a plying unit
Implementation Method 3
heat treatment of the carbon nanotube yarn that has passed through the plying unit
Implementation Method 4
heat treatment of the carbon nanotube yarn that has passed through the plying unit
Implementation Method 5
densification during rotation of a plying unit
Implementation Method 6
densification during rotation of a plying unit
Implementation Method 7
a thin carbon nanotube strand is drawn out from a carbon nanotube, which is vertically grown on a silicon wafer, by Van der Waals' force exerted between edges of the carbon nanotubes
Data Source
AI summary
Surface field electron emitters using a carbon nanotube yarn and a method of fabricating the same are disclosed. To fabricate the carbon nanotube yarn for use in fabrication of simple and efficient carbon nanotube field electron emitters, the method performs densification of the carbon nanotube yarn during rotation of a plying unit and heat treatment of the carbon nanotube yarn that has passed through the plying unit without using organic or inorganic binders or polymer pastes. The method fabricates the carbon nanotube yarn with excellent homogeneity and reproducibility through a simple process. The carbon nanotube yarn-based surface field electron emitters can be applied to various light emitting devices.