Super-aligned carbon nanotube film and its application in touch panels Shoushan Fan Department of Physics Tsinghua-Foxconn Nanotechnology Research Center Tsinghua University Beijing, China

GOAL To make carbon nanotubes useful! Tsinghua-Foxconn Nanotechnology Research Center Tsinghua University, Beijing, China GOAL To make carbon nanotubes useful! 2

Reality and Dreams of Carbon Nanotubes The Reality The Dreams Field emission Nanoelectronics Sensors Photonics SPM probes Composites … Laser Ar C-H Arc discharge Laser ablation CVD To Make Carbon Nanotubes in Order

Breakthrough in Making Orderly CNTs Science 283 (1999) 512 Radom Aligned Super-Aligned Nature 419 (2002) 801 CNT Films

Anisotropic Conductivity, CNT Films and Unique Properties 1cm 8-inch wafer Transparent, Anisotropic Conductivity, Flexible, Polarized Free of catalyst 8” wafer 300m long film

Carbon Nanotube Film Touch Panel CmHn Advantages Replacing indium with carbon Truly flexible and durable, Suitable for 3-D molding No photolithography, due to anisotropic conductivity High transparency, due to polarization of the CNT film Advanced Functional Materials, 20 (2010) 885; 21 (2011) 2721   

Features of CNT Touch Panels Radius of flexture: 5mm CNT Film Fixing Frame Sliding Path: 120mm Bending Test Truly Flexible

Features of CNT Touch Panels CNT touch panels are durable Pen Pitting Durability Test Scrape Durability Test Weight: 500g Pen size: 0.8mm (diameter) Frequency: 3 knocks/sec. Total: > 2 KK knocks (Pass) Knocked side: Film-side Scrape side: Film-side Function Test : PASS GLASS+FILM PMMA+FILM Pen Pitting Test Scrape Test CNT-Sensor CNT-Sensor PMMA PMMA

Features of CNT Touch Panels Optimized transparency for polarized light CNT Film Nature light e CNT Film LCD Polarization of light e CNT Film Parallel Perpendicular Polarization of light Parallel 45 degree Perpendicular

Features of CNT Touch Panels Low reflectivity (3% less) ITO Low reflectivity (3% less) Water proof Anti-inteference Touch force sensing

ITO CNT Processing Comparison: CNT & ITO CmHn CVD Raw materials Forming films Patterning Vacuum Evaporation Sputtering Indium & Tin Mining Smelting Target preparation Lithograph Etching Expensive facilities Pollution ITO Dry pulling CmHn CVD 6000C 30min NO Patterning CNT For making 100 million TP, CNT processing saves 9 million kwh of electricity and 1 million tons of water

8”- CNT Wafer: Mass Production

CNT Touch Panel: Mass Production 2,000 m2 cleanroom 2 million 4-7” CNT touch panels per month

CNT Touch Panel: Commercialization 2002 2005 2008 2012 Will.i.am 25 million CNT touch panels have been sold

Markets ? SACNT Wafer: Potential Applications 4-inch wafer 8-inch wafer 12-inch Quartz wafer Super aligned carbon nanotubes Carbon nanotubes with clean wall surface No catalyst in CNT arrays Easy to be patterned and transferred Markets ?

CNT Wires: Ultrathin and Strong Cu coated CNT wires Ultra-thin diameter, High tensile strength, High flexibility Low weight, bio-compatible

CNT Papers: Mass Production High permeability Bio-compatible Parallel laying Cross laying Conducting Flexible Anti-corrosion High permeability Bio-compatible

CNT films for Lithium Ion Batteries Conductive network Structural scaffold Lightweight and flexible CNT film current collectors Flexible and high strength Better rate performance and excellent cycling Lightweight and higher energy density Adv. Mater. 2012, 24, 2294 ; Adv. Funct. Mater., 2013, 23, 846 ; Nano Lett., 2013, 13, 818

CNT-film/Polymer Composite Actuators Anisotropic conductivity

Carbon Nanotube Film Heating Devices Polarized light Micro-heater array Flexible heater Uniform heating Flexibility Fast temperature response Addressable micro-heater arrays Looking for Real Applications Advanced Materials, 21( 2009) 3563

Thermo-Acoustic Effect: CNT Film Speaker Transparent, Flexible, Stretchable Speaker Nano Letters，8 (2008) 4539

CNT thermoacoustic chips Prototype Samples of CNT Speaker Nano Lett. 13 (2013) 4795

Acknowledgment National Basic Research Program of China National Science Foundation of China Foxconn Technology Group

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