OLED Components (FROM HOWSTUFFWORK.COM)

Like an LED, an OLED is a solid-state semiconductor device that is 100 to 500 nanometers thick or about 200 times smaller than a human hair. OLEDs can have either two layers or three layers of organic material; in the latter design, the third layer helps transport electrons from the cathode to the emissive layer. In this article, we'll be focusing on the two-layer design.

An OLED consists of the following parts:

  • Substrate (clear plastic, glass, foil) - The substrate supports the OLED.
  • Anode (transparent) - The anode removes electrons (adds electron "holes") when a current flows through the device.
  • Organic layers - These layers are made of organic molecules or polymers.
    • Conducting layer - This layer is made of organic plastic molecules that transport "holes" from the anode. One conducting polymer used in OLEDs is polyaniline.
    • Emissive layer - This layer is made of organic plastic molecules (different ones from the conducting layer) that transport electrons from the cathode; this is where light is made. One polymer used in the emissive layer is polyfluorene.
  • Cathode (may or may not be transparent depending on the type of OLED) - The cathode injects electrons when a current flows through the device.