Analysis of the structure type and working principle of OLED part two

2. Manufacturing of OLEDs

The most important part of the OLED production process is the application of the organic layer to the substrate. There are three ways to accomplish this:

1. Vacuum deposition or vacuum thermal evaporation (VTE) 

The organic molecules in the vacuum chamber are slightly heated (evaporated), and these molecules then condense as a thin film on the cooler substrate. This method is expensive but less efficient.

2. Organic Vapor Deposition (OVPD)

In a low pressure hot wall reaction chamber, the carrier gas transports the evaporated organic molecules to the low temperature substrate, and then the organic molecules condense into a thin film. Using a carrier gas can improve efficiency and reduce the cost of OLEDs.

3. Inkjet printing

Using inkjet technology, OLEDs can be sprayed onto the substrate, just as ink is sprayed onto paper during printing. Inkjet technology has greatly reduced the cost of producing OLEDs and can also be used to print OLEDs onto films with very large surface areas for the production of large displays, such as 80-inch large-screen TVs or electronic signage boards.

3. The light-emitting process of OLED 1.3

OLEDs emit light in a similar way to LEDs, going through a process called electrophosphorescence.

The specific process is as follows: 

1. The battery or power supply of an OLED device applies a voltage across the OLED.

2. Current flows from the cathode to the anode and through the organic layer (current refers to the flow of electrons).

3. The cathode outputs electrons to the organic molecular emission layer. 

4. The anode absorbs electrons from the organic molecular conduction layer. (This can be seen as the anode outputting holes to the conduction layer, the effect of which is equal.

5. At the junction of the emission layer and the conduction layer, electrons will combine with holes.