Organic Electronic Materials

Organic electronic materialsby SUNNY TANTIA R on 11/11/09,[object Object],OLED,[object Object]

INTRO:,[object Object],[object Object]

Organic electronic and their hybrid materials posses conducting ,semiconducting and light emitting properties

There active materials are processed over large areas of plastic or paper at lower temperatures

Organic electronics are lighter, more flexible ,less expensive, biodegradable than their inorganic counterparts,[object Object]

CHARGE TRANSFER COMPLEX AND CONDUCTIVE POLYMERS,[object Object],Organic electronic materials,[object Object]

CHARGE TRANSFER COMPLEXES,[object Object]

CT complexes are molecular groups where one is electron donating(donor) and other is electron accepting(acceptor).,[object Object],There is a partial transfer of electronic charge from donor to the acceptor in the excited molecular state. CT complexes have transition between excited molecular state and ground state.,[object Object],In 1973, a CT complex of TTF-TCNQ was the first organic conductor discovered, where TTF and ,[object Object],DONOR ACCEPTOR,[object Object], TCNQ are stacked independently and electron transfer from donor to acceptor takes place.,[object Object],Charge transfers are also observed between transition metal ions and ligands.,[object Object],A ligand metal charge transfer takes place when electrons are donated from Ligands to high oxidation state Metal Centre[LMCT] (e.g.., intense purple colorof a solution of permanganate),[object Object],The reverse, a Metal-to-Ligand Charge Transfer[MLCT] occurs when ligands containing accessible antibonding metal orbital's are coordinated with electron rich metal centre’s. ,[object Object],In 1980, first organic superconducting polymer called Tetra methyl tetraselenafulvalene-phosphorous –hexafluoride TMTSF2PF6 was discovered with a superconducting capacity at 0.9K at a pressure of 12kbar.,[object Object],Since 1980, organic superconductors with critical temperatures raised over 100K are synthesized, with several amazing properties and numerous applications. ,[object Object]

CONDUCTING POLYMERS,[object Object],[Having alternate double bonds],[object Object],CONJUGATED POLYMERS AND MOLECULES,[object Object],sp2 HYBRIDISED:σ and π bounds,[object Object],Conjugated polymers Small molecules,[object Object]

Conductive polymers are organic semiconductors including polyacetylenes, polypyrroles, polythiophenes, polyanilines,polyflurenes,polynaphthalenes, poly p-phenylenesulphide, poly p-phenylenevinylene .,[object Object],Melanin pigment in animals is a mixed copolymer of polyacetylene, polypyrrole, polyaniline. Fungal melanins are pure polyacetylenes and hence they are often called as MELANINS or ‘BLACKS’,[object Object],Conductive organic polymers have extended delocalized bonds similar to band structures in silicon but with localized states.,[object Object],Electronic conductivity can be increased by introducing charge carriers in valence or conduction band[DOPING],[object Object],Delocalization can be accomplished by formation of conjugated backbone of continuous overlapping orbital's(e.g.., alternating single and double C-C bond can form a continuous path of overlapping p-orbital’s.In polyacetylenes this creates degeneracy in the frontier molecular orbital's[highest occupied and lowest unoccupied orbital’s namely HOMO and LUMO . This leads to filled(electron containing) and unfilled bands similar to valence and conduction bands in semiconductors).,[object Object],Conduction mechanisms involves resonance stabilization, delocalization of pi- electrons along entire polymer backbones, as well as mobility gaps ,tunneling and phonon assisted hopping. ,[object Object],Tunneling is the quantum mechanical process by which a particle can penetrate a classically forbidden region of space,[object Object],Frequency hopping is one of two basic modulation techniques used in spread spectrumsignal transmission. It is the repeated switching of frequencies during radio transmission, often to minimize the effectiveness of "electronic warfare" - that is, the unauthorized interception or jamming of telecommunications.,[object Object]

Molecular orbital’s:,[object Object]

OLED:,[object Object],An OLED is a thin film LED in which the emissive layer is an organic compound.,[object Object],When this layer is polymeric (or plastic), OLEDs can be deposited in rows and columns on a screen using simple printing methods that are much more efficient than those used in manufacturing traditional LEDs.,[object Object],A key benefit of OLEDs is that they don’t need a backlight to function.,[object Object],An electron and hole pair is generated inside the emissive layer. When the electron and hole combine, a photon is produced, which will show up as a dot of light on the screen. Many OLEDs together on a screen make up a picture.,[object Object]

OLED energy level diagram,[object Object]

Color combinations produced using OLED,[object Object]

FLEXIBLE OLED and OTFT’s,[object Object]

Nobel prize in chemistry 2000,[object Object],[object Object],Nobel price in chemistry,[object Object],2000 !!!,[object Object],… are rewarded “for the discovery,[object Object],and development of electrically,[object Object],conductive polymers”.,[object Object]

Organic Electronic Materials

Organic Electronic Materials

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Organic Electronic Materials