OLED device fabrication crucial step

OLED devices produced include:
ITO / Cr glass cleaning - → lithography - → then wash - → pre-treatment - → vacuum evaporation multilayer organic layer (4-5 layers) - → vacuum evaporation back electrode - → vacuum evaporation protective layer - - → Packaging - → Cutting - → Test - → module assembly - → product testing, aging test and QC sampling process
Cleaning and surface treatment of ITO
ITO as an anode direct impact on the surface condition and the hole injection layer of the organic thin film and the electronic state of the interface between the film-forming organic material. If the dirty surface of ITO, the surface free energy becomes small, resulting in deposition of the hole transport material in the above condensation occurs, the film is uneven. ITO is usually the first surface of the wet processing, i.e. cleaning with detergent and then ethanol, and acetone, ultrasonic cleaning or vapor washing with an organic solvent, after the infrared light drying. Wash the activation treatment of the surface of ITO, increasing the oxygen content of the ITO surface layer in order to improve the work function of the surface of ITO can also ITO surface treatment with hydrogen peroxide, with a ratio of water: hydrogen peroxide: aqueous ammonia = 5:1: After a mixed solution of 1, the Character LCD Display device an order of magnitude increase in brightness. Because hydrogen peroxide causes the surface of ITO to reduce the tin content in excess of the proportion of oxygen increased, the increase in the work function of ITO surface thereby increasing the chance of a hole injection. UV - ozone and plasma surface treatment
Is the production of two methods commonly used in OLED Display Module devices, the main purpose is to:
1. ITO surface to remove organic residues.
2. To promote increased oxidation of the surface of ITO surface work function of ITO.
After degreasing the surface-treated surface of the work function of ITO is about 4.6eV, after UV - ozone or plasma surface-treated surface of the work function of ITO is about 5.0eV or more, the luminous efficiency and the working life will be increased. In the surface treatment of the ITO glass was dried in a vacuum must be in the operating conditions, an ITO glass not treated in air for too long, or ITO glass will lose its activity. The flatness of the substrate of the organic thin film patterns (morphology) is also crucial influence, since the surface roughness of the organic thin film on the surface of the contact patterns have a significant effect, so the insulating layer and the metal-level production of the need to select the production process.