OLED stuff

I was surfing for info on Apple's new tablet and found a reference to OLEDs and ...

>And you didn't have a clue what they were, right?
Uh ... right.
But, since curiosity is my forte, I looked about and larned that OLEDs can be used in a neat variety of ways:
  • Generate a display that you can fold up and stick in your pocket.
  • Paste to a wall, like wall paper ... and they can display moving images.
  • Provide bendable and very thin PC monitors.
  • Folding newspapers ... with a PC brain.
  • Make lighting fixtures that ...

Flexible display!

>Wait! What's OLED mean?
I though you'd never ask.
Remember that a Light Emitting Diode (LED) is a material that emits light when a voltage is applied.
Remember, too, that a source of voltage has two polarities: A negative cathode which ejects electrons and a positive anode which sucks up electrons.
Here's what I larned.
  • There are organic (carbon-based) molecules (like polyaniline), that have the property that
    • You apply a voltage across a layer of molecules.
    • Electrons get dragged out of the atoms.
    • They leave a "hole".
    • If you allow the electrons to plop back into the holes, light is emitted.
    • Various organic molecules provide various frequencies of visible light.
  • In OLEDs, there are (typically) two layers: Emmisive & Conductive.
    • The Emmisive layer is supplied with electrons by a Cathode.
    • The Anode sucks electrons from the Conductive layer, leaving holes.
    • Electrons in the Emmisive layer are attracted to the Anode and travel across the Emmisive/Conductive boundary.
    • They drop into the holes in the Conductive layer and ...
>And emit light!
You got it.
However, I think the holes in the Conductive layer actually migrate to the Emmisive layer and inkjet technology can be used to deposit OLED material and ...

>So why are you writing about this stuff? Isn't it explained elsewhere? Can't I just google?
Uh ... yes. That's where I get it, but I read stuff like:
"polyaniline (PANI) and Indium/tin oxide (ITO) as the transparent anode of a polymer light emitting diode with poly(2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene), (MEH-PPV), as the active layer"
And the diagrams are too complicated for me ... my eyes glaze over,
so I'm hoping to understand just enough without overtaxing these grey cells.

>That'll be difficult.

OLED structure