presentation by sunny tantia R

1. Organic electronic materialsby SUNNY TANTIA R on 11/11/09 OLED

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

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

6. CHARGE TRANSFER COMPLEX AND CONDUCTIVE POLYMERS Organic electronic materials

7. CHARGE TRANSFER COMPLEXES

8. CT complexes are molecular groups where one is electron donating(donor) and other is electron accepting(acceptor). 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. In 1973, a CT complex of TTF-TCNQ was the first organic conductor discovered, where TTF and DONOR ACCEPTOR TCNQ are stacked independently and electron transfer from donor to acceptor takes place. Charge transfers are also observed between transition metal ions and ligands. 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) 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. 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. Since 1980, organic superconductors with critical temperatures raised over 100K are synthesized, with several amazing properties and numerous applications.

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

10. Conductive polymers are organic semiconductors including polyacetylenes, polypyrroles, polythiophenes, polyanilines,polyflurenes,polynaphthalenes, poly p-phenylenesulphide, poly p-phenylenevinylene . 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’ Conductive organic polymers have extended delocalized bonds similar to band structures in silicon but with localized states. Electronic conductivity can be increased by introducing charge carriers in valence or conduction band[DOPING] 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). Conduction mechanisms involves resonance stabilization, delocalization of pi- electrons along entire polymer backbones, as well as mobility gaps ,tunneling and phonon assisted hopping. Tunneling is the quantum mechanical process by which a particle can penetrate a classically forbidden region of space 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.

12. Molecular orbital’s:

13. OLED: An OLED is a thin film LED in which the emissive layer is an organic compound. 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. A key benefit of OLEDs is that they don’t need a backlight to function. 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.

14. OLED energy level diagram

16. Color combinations produced using OLED

17. FLEXIBLE OLED and OTFT’s

20. Present scenario: Transformation of TECHNOLOGY!!!

21. Thank You for your attention!!