Preview

Organic Light Emitting Diodes

Powerful Essays
Open Document
Open Document
1994 Words
Grammar
Grammar
Plagiarism
Plagiarism
Writing
Writing
Score
Score
Organic Light Emitting Diodes
ORGANIC LIGHT EMITTING DIODES

DONE BY:
P.R.SESHADRI
ECE-B 3RD YEAR
30410106085
ORGANIC LIGHT EMITTING DIODES

INTRODUCTION
An OLED (organic light-emitting diode) is a light-emitting diode (LED) in which the emissive electroluminescent layer is a film of organic compound which emits light in response to an electric current. This layer of organic semiconductor is situated between two electrodes. Generally, at least one of these electrodes is transparent. OLEDs are used to create digital displays in devices such as television screens, computer monitors, portable systems such as mobile phones, handheld games consoles and PDAs.
There are two main families of OLEDs: those based on small molecules and those employing polymers. Adding mobile ions to an OLED creates a light-emitting electrochemical cell or LEC, which has a slightly different mode of operation. OLED displays can use either passive-matrix (PMOLED) or active-matrix addressing schemes. Active-matrix OLEDs (AMOLED) require a thin-film transistor backplane to switch each individual pixel on or off, but allow for higher resolution and larger display sizes.
WORKING PRINCIPLE :

[pic]

Schematic of a bilayer OLED: 1. Cathode (−), 2. Emissive Layer, 3. Emission of radiation, 4. Conductive Layer, 5. Anode (+)

A typical OLED is composed of a layer of organic materials situated between two electrodes, the anode and cathode, all deposited on a substrate. The organic molecules are electrically conductive as a result of delocalization of pi electrons caused by conjugation over all or part of the molecule. These materials have conductivity levels ranging from insulators to conductors, and therefore are considered organic semiconductors. The highest occupied and lowest unoccupied molecular orbitals (HOMO and LUMO) of organic semiconductors are analogous to the valence and conduction bands of inorganic semiconductors.

Originally, the most basic polymer OLEDs

You May Also Find These Documents Helpful

  • Good Essays

    LCD, LED & CRT

    • 1767 Words
    • 8 Pages

    A liquid-crystal display (LCD) is a flat panel display, electronic visual display, or video display that uses the light modulating properties of liquid crystals. Liquid crystals do not emit light directly.…

    • 1767 Words
    • 8 Pages
    Good Essays
  • Good Essays

    Phosphor: It is a key substance use to display in video display devices. This substance emits light when exposed to electron beam.…

    • 386 Words
    • 2 Pages
    Good Essays
  • Satisfactory Essays

    LED and Laser Transmitter

    • 347 Words
    • 2 Pages

    Light - emitting diode (LED) is a standard light source that carries low speed signals at short distances. LED light source is an all plastic fiber that transmits visible light. LED put out lower power and a bigger output pattern than laser light sources. LEDs have less bandwidth and are limiting to operate up to about 250Mhz or about 200Mbs. LED light sources do not contain hazardous material and last longer, about 10,000 hours. Bulbs generate less heat and it is friendlier to the environment because it used 5% less energy. LED transmitters are cheaper, they have a longer lifetime, and they more readily available.…

    • 347 Words
    • 2 Pages
    Satisfactory Essays
  • Powerful Essays

    In this experiment, one is to prepare a cadmium sulphide semiconducting film on the glass slides. The transition of electrons from the valence band to the conduction band can be achieved by the absorption of electromagnetic radiation, if this energy is equal to or larger than Eg. The excited electrons reaching its new energy level can absorb…

    • 990 Words
    • 4 Pages
    Powerful Essays
  • Good Essays

    Lcd vs Plasma

    • 773 Words
    • 4 Pages

    For instance, a plasma display is comprised of two parallel sheets of glass, which enclose a gas mixture usually composed of neon and xenon that is contained in millions of tiny cells sandwiched in between the glass. Electricity, sent through an array of electrodes that are in close proximity to the cells, excites the gas, resulting in a discharge of ultraviolet light. The light then strikes a phosphor coating on the inside of the glass, which causes the emission of red, blue or green visible light. Based on the information in a video signal i.e. DVD movie, TV signal or a video game, the television lights up thousands of tiny dots called pixels with a high-energy beam of electrons. In most systems, there are three pixel colors—red, green and blue—which are evenly distributed on the screen Each, pixel by the way, consists of one red, one blue and one green sub-pixel. The three colors in each pixel combine according to the amount of electric pulses fed to each sub-pixel, to create visible images.…

    • 773 Words
    • 4 Pages
    Good Essays
  • Satisfactory Essays

    Anil Duggal is a Chief Scientist at the GE Global Research Center in Niskayuna NY. Since receiving his doctorate from the Massachusetts Institute of Technology in 1992, he has led technology developments for GE in areas ranging from organic light emitting devices and wearable medical sensors to high power batteries and high efficiency solar modules. He is now responsible for catalyzing and maintaining innovation in the fields of electrical materials and systems. Anil has been granted 98 U.S. patents and received GE’s Coolidge Award in…

    • 86 Words
    • 1 Page
    Satisfactory Essays
  • Powerful Essays

    So biomedical engineers at Georgia Tech whipped up a special batch of maltohexaose, adding a molecule called a fluorescent tag. When struck by the correct wavelength of light, these molecules glow. (They absorb and then re-emit the light.)…

    • 1552 Words
    • 7 Pages
    Powerful Essays
  • Powerful Essays

    Sony

    • 848 Words
    • 3 Pages

    Sony holds the view that the OLED technology provides a markedly improved picture and it will be the basis for the next generation of television. At the same time, even very small televisions using the new OLED technology are significantly more expensive than LCD sets, and Sony fears that high prices could cause the limitation of sales. In recent years, Sony has been struggled and wants to ensure that it’s back on more sound footing before making the investment necessary to successfully commercialize the OLED technology now. In making this decision, Sony is taking the risk that it will lose the advantages that could come with being the top in the OLED market, also gain extra benefits associated with being an innovator in the technology industry. (Meanwhile, other companies such as LG Electronics and Samsung are making their own OLED televisions, and positioning themselves to gain first mover advantages.)…

    • 848 Words
    • 3 Pages
    Powerful Essays
  • Powerful Essays

    * Incandescent Bulbs- these are the standard bulbs that most people are familiar with. Incandescent bulbs work by using electricity to heat a tungsten filament in the bulb until it glows. The filament is either in a vacuum or in a mixture of argon/nitrogen gas.…

    • 2457 Words
    • 10 Pages
    Powerful Essays
  • Satisfactory Essays

    A light-emitting diode (LED) is a semiconductor light source.[6] LEDs are used as indicator lamps in many devices and are increasingly used for other lighting. Appearing as practical electronic components in 1962,[7] early LEDs emitted low-intensity red light, but modern versions are available across the visible, ultraviolet, and infrared wavelengths, with very high brightness.…

    • 260 Words
    • 2 Pages
    Satisfactory Essays
  • Powerful Essays

    Effect of Polarity

    • 4379 Words
    • 18 Pages

    between the cathode and the anode. The DC+ polarity samples were observed to have bainitic structure in the…

    • 4379 Words
    • 18 Pages
    Powerful Essays
  • Good Essays

    Syllabus of Rtu Ece Branch

    • 13430 Words
    • 54 Pages

    3EC2 - ELECTRONIC DEVICES & CIRCUITS UNIT 1: SEMICONDUCTOR PHYSICS: Mobility and conductivity, charge densities in a semiconductor, Fermi Dirac distribution, carrier concentrations and fermi levels in emiconductor, Generation and recombination of charges, diffusion and continuity equation, Mass action Law, Hall effect. UNIT 2: Junction diodes, Diode as a ckt. element, load line concept, clipping and clamping circuits, Voltage multipliers. Construction, characteristics and working principles of UJT UNIT 3: Transistor…

    • 13430 Words
    • 54 Pages
    Good Essays
  • Satisfactory Essays

    by passing a current or applying a potential. Electrochromic material is the one that change transmittance and/or reflectance which is associated with oxidation-reduction reaction. The color change is commonly between a transparent (“bleach”) state and color state, or between a two color states. In case more than two redox states, the electrochromic material may exhibit several colors and can be called multicolorelectrochromism. [1]…

    • 658 Words
    • 3 Pages
    Satisfactory Essays
  • Powerful Essays

    Biodegradable Electronics

    • 4153 Words
    • 17 Pages

    Organic I.INTRODUCTION The current era is encountering an emergence of new technologies and devices every single day. A team of U.S. scientists says it has developed a class of biodegradable electronics technology that could be utilized for a wide range of products — from consumer devices to medical implants — and that ultimately would dissolve completely, leaving no environmental impacts. Drawing on techniques that enable the production of systems using ultrathin sheets of silicon that dissolve in liquids, the so-called ―transient electronics‖[1] [2] technology has been used experimentally to make transistors, diodes, temperature sensors, and solar cells that degrade completely in even tiny amounts of water, the researchers say.…

    • 4153 Words
    • 17 Pages
    Powerful Essays
  • Good Essays

    Liquid Crystal Display

    • 1237 Words
    • 5 Pages

    We always use devices made up of Liquid Crystal Displays (LCDs) like computers, digital watches and also DVD and CD players. They have become very common and have taken a giant leap in the screen industry by clearly replacing the use of Cathode Ray Tubes (CRT). CRT draws more power than LCD and are also bigger and heavier. All of us have seen an LCD, but no one knows the exact working of it. Let us take a look at the working of an LCD.…

    • 1237 Words
    • 5 Pages
    Good Essays