ORGANIC ORGANIC ELECTRONICSELECTRONICS

Presented by:

Raghulal SethumadhavanRoll no.: 7627

Class: H7

Guided by: Dr. N.E. Jaffar

INTRODUCTION• Branch of electronics that deals with conductive

polymers, plastics, or small molecules which are carbon-based.

• As opposed to traditional electronics (or metal electronics) which relies on inorganic conductors such as Cu or Si.

• Includes organic semiconductors, organic dielectrics, conductors and light emitters.

• New applications include smart windows, rollable displays, electronic paper, etc.

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HISTORY

• In the 1950s, it was discovered that polycyclic aromatic compounds formed semi-conducting charge transfer complex salts with halogens

• This finding indicated that organic compounds could carry current.

• Alan J. Heeger, Alan G. MacDiarmid, and Hideki Shirakawa are credited for the "discovery and development" of conductive polymers and were jointly awarded Nobel prize in Chemistry in 2000

Why Organic Electronics?

• Organic Electronics products are lighter, more flexible

• Less expensive than their inorganic counterparts

• These are Biodegradable, being made from carbon

• Possible to achieve flexible structures• Performance

Comparison between Organic and inorganic Electronics

Technology growth

Conducting Polymers

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1977: First conducting polymer was found, Poly(acetylene)

By Shirakawa, MacDiarmid, Heeger

Conduction in Most Organic Semiconductors

• Van der Walls forces hold molecules together• Charge hopping, the major factor limiting mobility, takes

place from molecule to molecule• Phonons help e-’s hop, therefore increasing mobility• Mobility increases with temperature because of

phonons• Polarons, which appear as midgap states, decrease

mobility• Highly ordered structures and arrangement may

facilitate the intermolecular hopping process

Structures of some conjugated polymers

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Organic Electronic Devices

a.Flexible, microscale transistors patterned on a plastic substrate.

b. The first organic SRAM module, capable of storing 16kb in a small, plastic package, produced by Epson.

c. A low-cost black and white displaytechnology, pioneered by E-Ink

d. One of the most exciting applications envisioned for organic circuits -- roll-up displays.

(Cont.)

RFID tags

Inexpensive printed Radio FrequencyIDentification (RFID) tags will replace barcodesin some applications, giving packaging details and a great deal of self-information.

Organic transistors and memory

Organic transistors and memories will create new classes of products ranging frommultifunction smartcards to pharmaceutical packaging and could also create new opportunitiesfor the game, toy and greeting cards businesses.

Organic Thin-film-transistors (OTFTS)• OTFTs are transistors created using thin films,

usually of conjugated polymers deposited on glass.

• Here the source and drain electrodes are directly deposited onto the conducting channel, then a thin film of insulator is deposited in between

• OTFTs active layers can be thermally evaporated and deposited at much lower temperatures (i.e. 60° C)

Organic TFT tightness• Benefits

o Does not require a glass substrate as amorphous silicon does

o Low temperature manufactureo Could be made on a piece of

plastico Deposition techniques could

reduce costs dramatically• Challenges

o Workarounds for complications with photoresists

o Finding organic semiconductors with high enough mobilities & switching times

Applications

OTFTs for active-matrix displays Flexible view screens New generations of smart cards Organic Solar Cells Large-area display electronics

Organic Light Emitting Diode-OLED

•An OLED is a thin-film LED inwhich the emissive layer is an organiccompound.•The emissive electroluminescent layer can include a polymeric substance that allows the deposition of very suitable organic compounds

In rows and columns on a flat carrier by using a simple "printing" method to create a matrix of pixels which can emit different colored light.

OLED is a display device that sandwiches carbon based films between the two electrodes and when voltage is applied creates light.

ORGANIC SOLAR CELLS

• A photovoltaic cell is a specialized

semiconductor diode that converts

visible light into direct current (DC) electricity.

• OPVC uses organic electronics – small organic molecules for light absorption and energy transport

• The main disadvantages associated with organic photovoltaic cells are low efficiency, low stability and low strength compared to inorganic photovoltaic cells.

Working principle of Organic Solar Cells

1. Absorption of incident light

by the active layer

2. Generation of charge

carriers

3. Collection of separated

charge carriers at contacts

4. Separation of positive and

negative charge carriers by

an asymmetry (junction)

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Single layer organic photovoltaic cell

• Made by sandwiching a layer of organic electronic materials between two metallic conductors,a layer of indium tin oxide (ITO) with high work function and a layer of low work function metal such as Al, Mg and Ca 

• The potential created by the different work functions pulls electrons to the positive electrode and holes to the negative electrode.

• Common organic materials used-phthalocyanine, polyacetylene etc

Bilayer organic photovoltaic cells

• Contains two different layers in between the conductive electrodes which differ in electron affinity and ionization energy

• The layer with higher electron affinity and ionization potential is the electron acceptor, and the other layer is the electron donor.

• Commonly used materials- C60 and perylene derivatives

Dispersed heterojunction photovoltaic cells

• In this type of photovoltaic cell, the electron donor and acceptor are mixed together forming a polymer blend

• Electrons move to the acceptor domains, then carried through the device and collected by one electrode, and holes are pulled in the opposite direction and collected at the other side.

Growth techniques-SPIN COATING

• Used to apply uniform thin films to flat substrates.

• An excess amount of a solution is placed on the substrate, which is then rotated at high speed in order to spread the fluid by centrifugal force.

• Rotation is continued until the desired thickness of the film is achieved. The applied solvent is usually volatile and evaporates. 

Vacuum thermal evaporation

• Involves the heating of an organic material in vacuum. 

• The substrate is placed several centimeters away from the source so that evaporated material may be directly deposited onto the substrate

• This method is useful for depositing many layers of different materials without chemical interaction between different layers.

Printable Electronics•Printed electronics is a set of printing methods used to create electrical devices.

•Printing typically uses common printing equipment, such as screen printing, flexography, gravure, offset lithography and inkjet.

•Electrically functional electronic or optical inks are deposited on the substrate, creating active or passive devices, such as TFTs or resistors.

PRINTED OPTICS AND ELECTRONICS

•Flexible and thin

•Low-cost and simple

•Embedded, disposable

•Applications: smart packages, displays, sensors

Printing enable cost effective, high speed mass production

Roll-to-roll manufacturing production in km use and sale in cm Electronic intelligence everywhere

2007 2008 2009 2010 2011 2012

Components, circuits, integration-on-web, systems-on-foil, embedding 'electronics from inks' into products

R2R processes & production equipment

Materials

APPLICATION ROADMAPPING AND TIMESCALING

The market for organic and printable electronics is expected to be a $35 billion industry by 2015and reach over $300 billion in 2025, that is, almost twice the size of the silicon industry today

Application area:

•Tamper-evidence of hermetically sealed food/pharmaceutical packages

•Evaluation of remaining shelf-life of packed product

•Evaluation of use-by date of perishable products in opened package at home

Ink-jet printed package leak indicators

Imaging quality indicators with mobile phone

Conclusion

• Organics outshine their inorganic counterparts in simple deposition techniques, low cost and tunable properties.

• Organic electronics therefore offer the prospect of improving current technologies, as well as the development of those that were previously impossible.

• Future of organic electronics:• Portable compact screens.• Lab on a chip.• Smart Textile

Reference

• C.D. Dimitrakopoulos and P.R.L. Malenfant. “Organic Thin Film Transistors for Large Area Electronics” Adv. Mater., 14, No. 2, (January 16 2002)

• “The path to ubiquitous and low-cost organic electronic appliances onplastic.” Stephen R. Forrest. Nature 428, 911-918 (29 April 2004)

• “Organic thin film transistors.” Reese, C; Roberts, M; Ling, M-M;Bao, Z Materials Today. Vol. 7, no. 9, pp. 20-27. (Sept. 2004)

• www.efymag.com

• www.wikipedia.com

Thank You