The absorption of infrared (IR) radiation by carbon nanotubes (CNTs) can be significantly influenced by both their structure—whether they are single-walled carbon nanotubes (SWCNTs) or multi-walled carbon nanotubes (MWCNTs)—and their functionalization.
### Structure
1. **Single-Walled Carbon Nanotubes (SWCNTs)**:
- **Electronic Properties**: SWCNTs can exhibit either metallic or semiconducting properties depending on their chirality (the