Light Emitting Polymers L E P Presented by : Arun Krishnan R S

CONTENT INTRODUCTION HISTORY ARCHITECTURE WORKING MANUFACTURING TYPES OF LEPS APPLICATIONS ADVANTAGE DISADVANTAGES CONCLUSION references

INTRODUCTION Polymer which emits light(EM radiations)is using . Polymers are chains of smaller molecular components called MONOMERS.

HISTORY 1977 conducting polymers are discovered. Alan J. Heeger , Alan G. MacDiarmid got Nobel prize for chemistry in 2000. From this OLED evolved. In 1990 Friend et al found Electroluminescence in the conducting polymers. Birth of “LIGHT EMITTING POLYMERS”!!!!!!!!!!! Poly phinylene vinylene (PPV) is the first LEP discovered.

ARCHITECTURE Thin film of semiconducting polymer sandwiched between an ANODE and CATHODE. ANODE: ITO(Indium Tin Oxide) CATHODE: Metals (depends upon the type of LEP) SUBSTRATE: Glass, clear plastic (depends upon the type of LEP) Voltage is applied between anode and cathode

WORKING Due to applied voltage electrons and holes will migrate to polymer lattice. They will combine together to form excitons. Excitons returns to initial state by emitting radiation.

manufacturing In two types 1 : Spin coating 2 : Inkjet printing

manufacturing SPIN COATING A spin-coating machine is used that has a plate spinning at the speed of a few thousand rotations per minute.

manufacturing PRINTER BASED TECHNIQUE The most advanced is ink-jet printing. Resolution as high as upto 360 dpi Easier way to make large-screen displays. Printing promises much lower manufacturing cost.

TYPES OF LEPS Flexible Stacked organic(SOLEP) Transparent organic(TOLEP)

APPLICATIONS Multi or full color cell phone displays Full color high-resolution personal digital assistants(PDAs) Lightweight wrist watches Roll-up daily refreshable electronic newspapers Automobile light systems without bulbs

ADVANTAGES • Require only 3.3 volts and have lifetime of more than 30,000 hours. • Low power consumption. • Self luminous. • No viewing angle dependence. • Display fast moving images with optimum clarity. • Cost much less to manufacture because the active material is plastic. • Can be scaled to any dimension.

DISADVANTAGES Voltage drops may affect the performance. Limited market availability. Aging of LEP Light intensity gradually decreases. Disintegrate due to contact with oxygen.

CONCLUSION It has both electrical and optical property. It is simpler &cheaper. It permits flexible lighting and display . It is technology better the future.

references www.google.com www.wikipedia.com