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03 JUN

The luminescence principle, panel structure and key technology of organic light-emitting diode are analyzed deeply

  • Life Style
  • SABRINA
  • Dec 05,2023
  • 146

The luminescence principle, panel structure and key technology of organic light-emitting diode are analyzed deeply

OLED is an organic light-emitting diode, meaning "organic light-emitting display technology" in Chinese. The principle is that there is an organic luminescence layer sandwiched between the two electrodes, which emits light when the positive and negative electrons meet in the organic material, and the production cost is only 3-4% of the TFT LCD. In addition to being cheap to manufacture, OLED has many advantages, such as its own light-emitting properties. At present, the LCD needs a backlight module (backlight tube), but the OLED automatically emits light after starting, saving the weight, volume and power consumption of the bulb (accounting for nearly half of the LCD), not only reducing the thickness of the product to about 2 centimeters, but also reducing the working voltage to 2-10 volts. In addition to OLED reaction time (less than 10 milliseconds) and color than TFT LCD outstanding, more flexibility, making it a wide range of applications.

Structure and luminescence principle of organic light-emitting diode

The basic economic structure of OLED is to make a layer of organic chemiluminescence technology material that takes several decades to be nano-thick on indium tin oxide (ITO) glass as a luminous layer, and there is a layer of metal with low work function as an electrode above the luminous layer, forming a structure like a sandwich.

The basic structure of organic light-emitting diodes includes:

The luminescence principle, panel structure and key technology of organic light-emitting diode are analyzed deeply

Substrate (clear plastic, glass, foil)- The base is used to support the entire OLED.

Anode (transparent)- When current flows through the device, the anode eliminates electrons (increasing electron "holes").

Hole transport layer - This layer consists of organic bonded material molecular structures, which study the molecular data transfer from the anode "holes".

Luminescent layer - a layer of organic material molecules (as opposed to the conductive layer) in which the luminescence process takes place.

Electron transport layer - This layer consists of organic material molecules that transport "electrons" from the cathode.

Cathode (depending on the type of OLED, it can be transparent or opaque) - When a current flows through the device, the cathode injects electrons into the circuit.

Organic light-emitting diode is a kind of double injection light-emitting device. Driven by the applied voltage, the electrons and holes injected by the electrode are combined in the luminescent layer to form electron-hole pairs with bound levels, namely excitons, which radiate to inactivate photons and produce visible light. In order to enhance the injection and transport ability of electrons and holes, a hole transport layer is usually added between the ITO and the luminescent layer, and an electron transport layer is added between the luminescent layer and the metal electrode, thereby improving the luminescent performance. Where the holes are injected by the anode and the electrons are injected by the cathode. Holes jump in the highest occupied molecular orbital (HOMO) of the organic material, and electrons jump in the lowest unoccupied molecular orbital (LUMO) of the organic material.