Indium tin oxide (ITO) substrate pre-treatment Character LCD Modules

(1) ITO surface roughness: ITO has been widely used in the commercial manufacture of display panels having a high transmittance, low resistivity and a high work function, etc.. In general, the use of RF sputtering (RFsputtering) manufactured by ITO vulnerable to poor process control factors lead to an uneven surface and, thus, the surface of the tip of the substance or protrusions. In addition, the high-temperature calcination and recrystallization process will produce about 10 to 30 nm or the protruding layer surface. These path to provide a hole is formed between the planarization layer of fine particles and fired directly at the opportunity of the cathode, these intricate path causes the increase of leakage current. Usually there are three ways to solve this surface layer? U One is to increase the thickness of the hole-injecting layer and the hole transport layer to reduce the leakage current, this method is used for PLED and the hole layer thicker OLED (200 nm). Second, the ITO glass processing, make the surface smooth. Third, the use of other coating methods to better surface roughness.TFT Lcd Modules
(2) the increase of the ITO work function: When the hole injection from ITO HIL, too much potential energy difference Schottky barrier, so that the hole is not easy to inject, how to reduce the potential energy difference of the ITO / HIL interface ITO The focus of the pre-treatment. Usually we use the O2-Plasma way to increase the saturation of the ITO, an oxygen atom, in order to achieve the purpose of increasing the work function. 4.8eV up to 5.2eV the ITO by O2-Plasma treatment work function from the original, and the work function of the HIL is already very close.
Join the auxiliary electrode, due to the the OLED current drive components, when the external line is too long or too small, the external circuit will cause severe voltage gradient, the fall in the real the OLED component of the voltage drop, the panel luminous intensity decreases. ITO resistance is too large (10ohm/square), could easily lead to the external unnecessary power consumption, an additional auxiliary electrode to reduce the voltage gradient into increased luminous efficiency, reduce the drive voltage shortcut. Chromium metal (Cr: Chromium) is the most commonly be used as the auxiliary electrode material, it has the advantages of good stability to environmental factors, and greater selectivity of the etching solution. However, its resistance value in the film 100nm 2ohm/square, in some applications, is still too large, and therefore has a lower resistance value to the same thickness of aluminum (Al: Aluminum) metal (0.2ohm/square) auxiliary electrode another better choice. However, the high activity of the aluminum metal to reliability aspects of the problem Accordingly, the multi-laminate of the auxiliary metal were proposed, such as: Cr / Al / Cr or Mo / Al / Mo, such a process, however, increase the complexity and costs, the auxiliary electrode material of choice to become one of the priorities in the OLED technology.Character LCD Display