Silver Nanorods (AgNRs)
Synthesis Methods
Seed-Mediated Growth Method: Uses silver seeds in a controlled growth environment with surfactants like cetyltrimethylammonium bromide (CTAB) to direct rod formation.
Electrochemical Deposition: Silver nanorods are grown on conductive substrates using templated electrodeposition techniques.
Photochemical Reduction: UV or visible light is used to control the nucleation and anisotropic growth of nanorods.
Polyol Method: Uses ethylene glycol as both the reducing agent and solvent, often combined with polyvinylpyrrolidone (PVP) for shape control.
Applications and Uses
- Surface Plasmon Resonance (SPR) Sensors: Due to their anisotropic shape, silver nanorods exhibit strong and tunable plasmonic properties, making them ideal for biosensors and environmental monitoring.
- Metamaterials: Used in plasmonic metamaterials to manipulate light beyond the diffraction limit, enhancing applications in optics and telecommunications.
- Transparent Conductive Films: Silver nanorods form highly conductive, flexible thin films for touchscreens, OLEDs, and photovoltaic devices.
- Photothermal Therapy (PTT): Silver nanorods efficiently absorb near-infrared (NIR) light, converting it into localized heat to target cancer cells.
- Biosensing and Diagnostics: Employed in label-free detection of biomolecules using localized SPR techniques.
- Antimicrobial Coatings: Like silver nanoparticles, silver nanorods exhibit strong antibacterial effects and are used in medical textiles, wound dressings, and implants.
- Catalysis for Chemical Reactions: Silver nanorods enhance catalytic reactions in organic transformations and pollutant degradation.
- Water Purification: Incorporated into filtration membranes for antimicrobial and photocatalytic degradation of contaminants.
- Thermal Management: High thermal conductivity enables applications in heat dissipation materials for electronics and LED cooling.
- Highly Conductive Inks: Silver nanorod-based inks are used in printed circuit boards (PCBs), RFID antennas, and flexible electronics.
- Electrodes for Batteries and Supercapacitors: Silver nanorods improve charge transfer and efficiency in lithium-ion batteries and supercapacitors.
- Plasmonic Enhancement in Solar Cells: Utilized in light-trapping strategies to enhance the efficiency of thin-film and perovskite solar cells.
Technical Properties
Chemical Formula: Ag
Shape: Rod-like nanostructures with high aspect ratios (length-to-diameter ratio)
Density: 10.49 g/cm³
Melting Point: ~961.8°C
Electrical Conductivity: ~63 × 10⁶ S/m (high electrical conductivity)
Thermal Conductivity: ~429 W/m·K (excellent heat transfer properties)
Optical Properties: Strong surface plasmon resonance (SPR), tunable from visible to near-infrared (NIR) wavelengths
Stability: More resistant to oxidation compared to silver nanoparticles due to anisotropic shape