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Process of CNT paste. dispersion of CNT powder flow property control mechanical cutting of CNT. Composition design of CNT paste. Premixing &Three Roll Milling. Viscosity : 20000~50000cp Visco-elastic behavior. Carbon Nanotube. Screen Printing & Drying. Backside Exposure & Development.
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Process of CNT paste • dispersion of CNT powder • flow property control • mechanical cutting of CNT Composition design of CNT paste Premixing &Three Roll Milling Viscosity : 20000~50000cp Visco-elastic behavior Carbon Nanotube Screen Printing & Drying Backside Exposure & Development • firing at 90~200℃ remove solvent • firing at 300~400℃ burn out organic • firing at 400~500℃ enhance adhesion Firing Inorganic Binder Activation treatment • stable and uniform emission property • using adhesive tape Characterization Organic Vehicle Applications of CNT paste Field Emission Display (FED) Back light unit for TFT-LCD Synthesis and Application of CNT Paste
Problems of CNT paste using frit - low uniformity of cathode layer - weak adhesion - aggregation of frit during firing <CNT paste with frit > substrate Advantage of SOG as inorganic binder - good adhesion - uniform cathode layer - simple dispersion < CNT paste with SOG > enhanced emission properties of CNT paste substrate CNT Paste for Field Emission Display ▶Improvement of film uniformity and adhesion property through change of inorganic binder from glass frit to spin on glass (SOG) Emission properties of CNT paste with different inorganic binder Current density at electric field of 5V/µm Electric field at current density of 300µA/cm2 The emission properties of CNT pastes with SOG were stable and uniform although sintering was carried out at relatively high annealing temperature of 450oC under air. SOG is more suitable inorganic binder than frit for FED application
Emission stability of CNT paste Life time measurement at different current density as electrical aging • - base pressure : ~ 1.0 ×10-6 Torr • - spacing between anode and cathode : 600µm • I-V measurement after tape activation treatment • and multi-cycling 2.43mA/cm2 1.16mA/cm2 Life time measurement at current density of 3mA/cm2 2.1mA/cm2 (-30%) 1.92mA/cm2 (-36%) Emission uniformity of CNT paste Line patterned sample 2cm - 6 mA/cm2 @ 2.4V/µm - Brightness : 18000cd/m2 2cm Emission Stability and Uniformity of CNT Paste