Improving the field emission from carbon nanotubes through chemical functionalisation: a quantifiable approach

Area of Science:

• Materials Science
• Surface Chemistry
• Physics

Background:

• Electron emission from carbon nanotubes (CNTs) is crucial for applications like field emission displays and vacuum electronics.
• Enhancing electron emission current typically involves increasing local electric fields or lowering the emission potential barrier.
• Surface chemical modification of CNTs is primarily used for dispersion, often neglecting its impact on emission properties.

Purpose of the Study:

• To investigate the impact of chemical modification on the field emission properties of carbon nanotubes.
• To demonstrate that chemically induced changes to the nanotube work function can significantly improve electron emission current density.
• To calculate the interdependencies between local electric field and work function for achieving specific current densities.

Main Methods:

• Surface functionalization of carbon nanotubes via chemical modification.
• Characterization of modified CNTs to assess changes in work function.
• Fabrication and testing of CNT-based arrays to measure field emission current density.
• Theoretical calculation of electric field and work function requirements for target current densities.

Main Results:

• Chemical modification of CNT surfaces leads to significant improvements in electron emission current density.
• Altering the nanotube work function is a viable strategy for enhancing field emission performance.
• The study quantifies the relationship between work function, local electric field, and emission current density.
• Optimized chemical treatments can reduce the operational electric field requirements for CNT emitters.

Conclusions:

• Chemically induced changes to the work function of carbon nanotubes offer a powerful method for enhancing electron emission.
• Surface chemistry plays a critical role in the field emission behavior of CNTs, beyond just dispersion.
• This research provides a pathway to design more efficient CNT-based electron emitters by controlling surface properties.