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PERFORMANCE ANALYSIS OF LUMINESCENT MATERIALS FOR OLED APPLICATIONS

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PERFORMANCE ANALYSIS OF LUMINESCENT MATERIALS FOR OLED APPLICATIONS

  1. 1. Presentation On SEMINAr-1 (2ND Semester) Amity School of Engineering and Technology Amity University Uttar Pradesh Lucknow “PERFORMANCEANALYSISOF LUMINESCENT MATERIALS FOR OLED APPLICATIONS: a REVIEW” Guide: Submitted By: Prof.(Dr.) Ashok Kumar Mishra Adrija Chowdhury M.Tech (OEOC) A7636913003 26 May 2014 1
  2. 2. Oled: what is it???  Small LED displays showing only the numeric contains.  Heavy jumbo CRTs: heavy & bulky requiring quiet larger area than anything else; couldn’t be carried from one place to another.  Compact LCDs: very lighter in weight; easily carried; drawback of getting the perfect result in some particular direction.  Lightweight, efficient and flexible display technology, based on OLEDs emerged: Solid-state semiconductor device 100 to 500 nm thick; 200 times smaller than a human hair. Consists of a luminescent organic semiconducting layer sandwiched between two electrodes and deposited on a substrate. 26 May 2014 2
  3. 3. Oled generalized structure 26 May 2014 3  Substrate (clear plastic, glass, foil): supports the OLED. Anode (usually ITO): Transparent to visible light Cathode: metals like barium, calcium and aluminium are used as a cathode Organic layers: made of organic molecules or polymers. They are of two types: Conducting layer - transport "holes" from the anode. E.g: polyaniline. Emissive layer - transport electrons from the cathode; emits light in response to an electric current. E.g: polyfluorene.
  4. 4. Working mechanism The battery or power supply of the device containing the OLED applies a voltage across the OLED. An electrical current flows from the cathode to the anode through the organic layers. (an electrical current is a flow of electrons) At the boundary between the emissive and the conductive layers, electrons find electron holes. The OLED emits light. 26 May 2014 4
  5. 5. PERFORMANCE ANALYSIS OF LUMINESCENT MATERIALS Based upon the type of Organic Semiconductor material used: SM-OLED v/s P-OLED Based upon the type of electroluminescence property: Fluorescence v/s Phosphorescence 26 May 2014 5
  6. 6. SM-OLED and p-oled 26 May 2014 6
  7. 7. Materials used in sm-oled 26 May 2014 7
  8. 8. Materials used in p-oled 26 May 2014 8
  9. 9. Device structure analysis: SM-OLED& P-OLED 26 May 2014 9
  10. 10. Characteristics curves analysis ofsm-oled andp-oled 26 May 2014 10 SM-OLED is better than P-OLED: in terms Of Efficiency and Lifespan; though Costlier
  11. 11. fLuorescence v/s phosphorescence Faster decay Durable for lesser time period Lesser efficient No spin change of excitons Emission occurs due to singlet state excitons only 26 May 2014 11 Slower decay Durable for longer time period Most efficient Involves spin change Both singlet and triplet state excitons are responsible for emission
  12. 12. characteristic curves for various parameters of oled 26 May 2014 12
  13. 13. 26 May 2014 13
  14. 14. Types of OLED 26 May 2014 14
  15. 15. Passive matrixoled Perpendicular cathode/anode strip orientation Light emitted at intersection (pixels) External circuitry •Turns on/off pixels External circuitry Large power consumption •Used on 1-3 inch screens •Alphanumeric display 26 May 2014 15
  16. 16. active matrix oled Full layers of cathode, anode, organic molecules Thin Film Transistor matrix (TFT) on top of anode •Internal circuitry to determine which pixels to turn on/off Less power consumed then PMOLED •Used for larger displays 26 May 2014 16
  17. 17. transparent oled Transparent substrate, cathode and anode Bi-direction light emission Passive or Active Matrix OLED Useful for heads-up display •Transparent projector •Screen •glasses 26 May 2014 17
  18. 18. Top emitting oled Non-transparent or reflective substrate Transparent Cathode Used with Active Matrix Device Smart card displays 26 May 2014 18
  19. 19. foldable oled Flexible metallic foil or plastic substrate Lightweight and durable Reduce display breaking Clothing OLED 26 May 2014 19
  20. 20. white oled Emits bright white light Replace fluorescent lights Reduce energy cost for lighting True Color Qualities 26 May 2014 20
  21. 21. Fabricationtechnologies  Polymer-based OLEDs: excellent film forming properties; ease of application over large surfaces through simple, economically viable coating techniques. e.g-ink jet printing. Small molecule materials: typically coated as thin films via vacuum-deposition which is difficult over large areas and is not as cost effective.  The techniques are as follows:  Vacuum deposition or vacuum thermal evaporation (VTE)  Organic vapor phase deposition (OVPD)  Inkjet printing  Transfer-printing 26 May 2014 21
  22. 22. Pros and cons  Much faster response  Consume significantly less power  Wider viewing angles  Thinner display  Better contrast ratio  Safer for the environment  Light weight  Cost efficient  Brighter  Lifetime: usage gets limited due to degradation of materials  Expensive manufacturing technologies  Susceptible to water 26 May 2014 22
  23. 23. applications 26 May 2014 23
  24. 24. Current trend and conclusion Manufacturers focusing on finding a cheap way to produce: “Roll-to-Roll Manufacturing” Increasing efficiency by: implementing multilayered structure; boosting lifespan OLED will replace current LED and LCD technologies based market Flexibility and thinness will enable many applications: may lead to future application: heads-up displays, automotive dashboards, billboard type displays, home and office lightings and flexible displays 26 May 2014 24
  25. 25. references www.google.com www.wikipedia.com www.electronics.howstuffworks.com www.oled-info.com www.oled-display.net http://www.cepro.com/article/study_future_bright_for_ole d_lighting_market/ http://www.technologyreview.com/energy/21116/page1/ http://optics.org/cws/article/industry/37032 26 May 2014 25
  26. 26. THANK YOU 26 May 2014 26

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