1. ORGANIC TRANSISTOR
TECHNOLOGY
SAMI UR REHMAN
1

2. Thin-film transistor (TFT) Sony
Technology
• Video link: http://www.youtube.com/watch?v=mtLfJ-mFsA8
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3. Organic Vs Inorganic Semiconductors
• Silicon based inorganic  Polymer based organic
material material
• Covalently bonded Van der Waals bonded
crystals crystals
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4. 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)
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5. Comparison of organic and Si based
technologies
Organic Electronic Silicon
Cost $5 / ft2 $100 / ft2
Fabrication Cost Low Capital $1-$10 billion
Device Size 10 ft x Roll to Roll < 1m2
Material Flexible Plastic Substrate Rigid Glass or Metal
Required Conditions Ambient Processing Ultra Cleanroom
Process Continuous Direct Printing Multi-step Photolithography
Courtesy: Sara Saedinia
University of California, Irvine SAMI UR REHMAN
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6. 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
6
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7. Displays (OLED)
• 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
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7
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8. Solar Cells
• The light falls on the polymer
• Electron/hole is generated
• The electron is captured C60
• The electricity is passed by the
nanotube
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8
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9. Organic Thin Film Transistors (OTFTs)
Organic material Organic material
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9
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10. An Example of an I-V of OTFTs
Lg = 20 µm
W = 220 µm
400 nm SiO2
50 nm organic
Courtesy: 10

11. Equipment and materials
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11
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12. 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.
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12
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13. 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
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14. 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
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14
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15. Glass substrate(Silicon TFT)
• Glass substrates can be used to prepare
organic photovoltaic cells and organic light
emitting diodes.
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15
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16. 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
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17. 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)
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17
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