Date post: | 24-Jan-2015 |
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Technology |
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ORGANIC TRANSISTOR TECHNOLOGY
SAMI UR REHMAN 1
Thin-film transistor (TFT) Sony Technology
• Video link: http://www.youtube.com/watch?v=mtLfJ-mFsA8
SAMI UR REHMAN (sami-rehman.blogspot.com)
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Organic Vs Inorganic Semiconductors
• Silicon based inorganic material
• Covalently bonded crystals
Polymer based organic material
Van der Waals bonded crystals
SAMI UR REHMAN (sami-rehman.blogspot.com)
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Advantages of organic electronics
• Organic electronics are lighter, more flexible
• Low-Cost Electronics
– No vacuum processing
– No lithography (printing)
– Low-cost substrates (plastic, paper, even cloth…)
– Direct integration on package (lower insertion costs)
SAMI UR REHMAN (sami-rehman.blogspot.com)
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Comparison of organic and Si based technologies
Cost
Fabrication Cost
Device Size
Material
Required Conditions
Process
Organic Electronic
$5 / ft2
Low Capital
10 ft x Roll to Roll
Flexible Plastic Substrate
Ambient Processing
Continuous Direct Printing
Silicon
$100 / ft2
$1-$10 billion
< 1m2
Rigid Glass or Metal
Ultra Cleanroom
Multi-step Photolithography
Sara Saedinia
University of California, Irvine
Courtesy:
SAMI UR REHMAN (sami-rehman.blogspot.com)
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Disadvantages of organic technology
• Conductive polymers have high resistance and therefore are not good conductors of electricity.
• Because of poor electronic behavior (lower mobility), they have much smaller bandwidths.
• Shorter lifetimes and are much more dependant on stable environment conditions than inorganic electronics would be.
SAMI UR REHMAN (sami-rehman.blogspot.com)
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• One of the biggest applications of organic transistors right now.
Organic TFTs may be used to drive LCDs and potentially even OLEDs, allowing integration of entire displays on plastic.
• Brighter displays
• Thinner displays
• More flexible
Displays (OLED)
SAMI UR REHMAN (sami-rehman.blogspot.com)
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Solar Cells
• The light falls on the polymer
• Electron/hole is generated
• The electron is captured C60
• The electricity is passed by the nanotube
SAMI UR REHMAN (sami-rehman.blogspot.com)
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Organic Thin Film Transistors (OTFTs)
Organic material Organic material
SAMI UR REHMAN (sami-rehman.blogspot.com)
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An Example of an I-V of OTFTs
Lg = 20 µm W = 220 µm 400 nm SiO2
50 nm organic
Courtesy: 10
Equipment and materials
SAMI UR REHMAN (sami-rehman.blogspot.com)
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PEDOT:PSS
• PEDOT:PSS or Poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) is a polymer mixture of two ionomers.
• Commercially available PEDOT:PSS products are produced by Heraeus with the trade name Clevios and by AGFA with the trade nameOrgacon.
• Heraeus Clevios™ P VP AI 4083 - one of the most commonly used PEDOT:PSS formulations for spin coated OPVs and OLEDs. Spins to ~40 nm at 5000 rpm.
SAMI UR REHMAN (sami-rehman.blogspot.com)
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PEDOT:PSS
Resistivity: 500-5000 ohm cm
Solid content: 1.3 to 1.7% Na content: 400 ppm maximum Sulfate content: 40 ppm maximum Viscosity: 5-12 mPa s PEDOT:PSS ratio: 1:6 Usage: <100 μl per standard (20 mm x 15 mm) substrate.
Price: £149 per 100ml
SAMI UR REHMAN (sami-rehman.blogspot.com)
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Encapsulation Epoxy
• Encapsulation epoxy can be used as an adhesive for organic light-emitting diodes and organic photovoltaics without damaging the polymer or cathode.
• In conjunction with a glass coverslip it can provide a robust barrier against ingress of oxygen and water to provide extended lifetimes for measurement and storage.
• Cost: £69 per 10 ml
SAMI UR REHMAN (sami-rehman.blogspot.com)
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Glass substrate(Silicon TFT)
• Glass substrates can be used to prepare organic photovoltaic cells and organic light emitting diodes.
SAMI UR REHMAN (sami-rehman.blogspot.com)
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Plastic Substrate
• Glass substrates (silicon TFT). are difficult to bend.
• However, a display with organic transistors on a plastic substrate would be completely flexible. Such a display could also be dropped without breaking, rolled up, or folded.
• PET, PEN or Kapton are the examples of flexible substrates
SAMI UR REHMAN (sami-rehman.blogspot.com)
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Dimatix materials printer dmp-2800
• The DMP-3000 has a printable area of 300 x 300 mm with a positional accuracy and repeatability of ± 5 µm and ± 1 μm, respectively.
• The DMP-3000 uses a temperature controlled vacuum platen to accurately register, maintain and thermally manage substrates during printing.
• These substrates include plastic, glass, ceramics, and silicon, as well as flexible substrates from membranes, gels, and thin films to paper products.
• Cost: US 49,000$ (including shipping cost)
SAMI UR REHMAN (sami-rehman.blogspot.com)
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