Nanowires

What Are Silver Nanowires?

Silver nanowires (AgNWs) are one-dimensional nanostructures composed of metallic silver with diameters typically between 20-100 nm and lengths ranging from 10 to 100 micrometers. Their extreme aspect ratios — often exceeding 1000:1 — allow nanowire networks to form electrically percolating pathways at very low areal densities, enabling transparent conductive films that combine high electrical conductivity with high optical transmittance.

Cheap Tubes synthesizes silver nanowires in-house at our Vermont facility using a polyol reduction method that yields 30 nm outer diameter nanowires in isopropanol (IPA) at 25 mg/mL concentration. Synthesizing in-house allows us to control aspect ratio, diameter distribution, and surface chemistry directly — parameters that critically affect transparent electrode performance.

Physical and Electrical Properties

Property	Value
Outer Diameter	30 nm (typical)
Length	10-100 um
Aspect Ratio	300-3000
Concentration	25 mg/mL in IPA
Film Sheet Resistance	<10 Ohm/sq at >85% transmittance
Optical Transmittance	85-95% (visible spectrum)
Flexibility	Maintains conductivity under repeated bending — ITO cracks at <1% strain

Applications of Silver Nanowires

Transparent Conductive Electrodes (TCEs)

The primary application for silver nanowires is as transparent conductive electrodes in touch panels, organic photovoltaics (OPV), OLEDs, and electrochromic devices. AgNW films achieve sheet resistances of 5-50 Ohm/sq at optical transmittance of 85-95% — matching or exceeding ITO. On flexible substrates where ITO would crack under bending, AgNW films are drop-in replacements. Junction resistance can be further reduced by UV sintering, thermal annealing at 150-200C, or acid treatment — improving conductivity by 2-5x.

Flexible and Stretchable Electronics

AgNW networks embedded in PDMS, PU, or PET films maintain conductivity under strains exceeding 100% — far beyond the less than 1% strain tolerance of ITO. This enables stretchable electrodes for epidermal electronics, electronic skin (e-skin), health monitoring patches, and soft robotics. Conductance of optimized AgNW/elastomer composites remains within 10% of initial value after thousands of stretch-release cycles.

Transparent Heaters and Defrosting Films

The combination of optical transparency and electrical conductivity makes AgNW films ideal for transparent heaters in automotive windshields, airplane windows, smart windows, and outdoor displays. At 5-12 V input, AgNW heaters rapidly reach 50-100C with response times under 60 seconds, defrosting surfaces or controlling liquid crystal orientation in smart glass.

EMI Shielding on Displays

Dense AgNW networks provide EMI shielding effectiveness of 20-40 dB while remaining highly transparent (>80%). This is uniquely suited for transparent EMI shielding on display screens, optical windows in military vehicles, and electromagnetic isolation of photovoltaic panels from internal electronics noise.

Electrochemical Biosensors

AgNW-modified electrodes demonstrate enhanced sensitivity for glucose, hydrogen peroxide, dopamine, and heavy metal ion detection. The nanowire geometry provides 10-100x more electroactive surface area per unit geometric area compared to flat silver electrodes, enabling nanomolar-range detection limits.

Deposition and Processing

Silver nanowire films are deposited from liquid suspension by spray coating (most common for large areas), spin coating (uniform films on wafer-scale substrates), bar coating (Mayer rod), slot-die coating (roll-to-roll compatible), and vacuum filtration (research). After deposition, films are annealed at 150-200C or treated with UV-ozone, acid, or pressure to reduce junction resistance. Embedding AgNW networks in polymer overcoats (PEDOT:PSS, PVA, polyurethane) improves adhesion and environmental stability.

Availability and Ordering

Cheap Tubes’ silver nanowires ship at 25 mg/mL in IPA. Custom concentrations (5-50 mg/mL), alternative solvents (water, ethanol, ethylene glycol), and surface coatings are available on request. Pricing ranges from $200-500/g depending on quantity. Contact us for volume pricing and custom specifications.