Engineering molecular bandgap by bottom-up synthesis of varied-width graphene nanoribbons
a) Synthesis of GNR heterojunctions from molecular building blocks 1 and 2. b) High-res STM (scanning tunneling microscope) image of GNR heterojunction, with larger-scale image of multiple junctions inset.
Connected pre-designed molecular building blocks to create shape-tunable graphene nanoribbons (GNRs), whose width and bandgap varies with atomic-scale precision along the length of a single GNR.
Significance and Impact
The ability to control and vary GNR width and the resulting bandgap enables creation and exploration of new molecular-scale heterojunctions with atomic precision.
- Synthesized individual molecules of different widths with specific functional groups that allow them to assemble via covalent bonding into width-varying graphene nanoribbons
- Used scanning tunneling and atomic force microscopy to characterize the resulting molecular structure and electronic properties, and compared experimental data to theoretical predictions
- Discovered new interface state; unprecedented control over nanoribbon shapes and properties