The Study Of A Multilayer Of Organic Inorganic Hybrid Thin Film Encapsulation Structure For Organic Light-emitting Diodes

As a huge wealth of new science and technology, organic light emitting phenomenon wasdiscovered as early as in the1960s. Compared with the other light-emitting technology, OLED_shave a broad application prospects in the display and lighting area because of its high plasticity,rich colors, high efficiency, and friendly environment. In1992,the Nobel laureate A.Heegermade flexible organic light emitting diode by polymer substrate and show its attractive side inthe front of us. The technology always develop to the direction toward human friendly. Alongwith the development of flexible and transparent display technology, you can imagine, in thenear future, the display can be like the printed newspaper, a roll-to-roll efficient preparation,and more light and portable. However water and oxygen in the air is the threat to FOLED.Japanese scholar C.Adachi reported that the luminance of OLED_s without encapsulationdecreased99%after150min in the air. Where in the destructive effects of oxygen mainly madethe light emitting layer material, generated hydroxy compounds.The main failure mode of thewater is that water reacted with a metal electrode of the device. Therefore, OLED_s must bepackaged to protect water and oxygen from reacting with it. To meet the practical requirementof the OLED_s, the Water Vapor Transmission Rate（WVTR） of thin film encapsulation must belower than1x10^-6g/m²/day,and oxygen permeability （OTR: Oxygen Transmission Rate） to beless than1x10^-3cm²/m²/day. Although traditional rigid packaging method can reach this target,but the cover is a non-bent glass or metal shell, and thus can not be used in the package ofFOLED. Improved method on flexible substrate is using epoxy adhesive flexible cover to blockmoisture and oxygen. However, after curing and cross linking the formation ofthree-dimensional mesh structure of the epoxy is easy to produce a large internal stress to brittleand crack, resulting in performance of the epoxy resign degradate. Compare with the rigidOLED_s, FOLED should be able to stand bending, stretching, shrink the role of external forces,and therefore. how to avoid FOLED packaged mechanical properties, becoming one of the keytechnologies of FOLED solved. In recent years, FOLED encapsulation technology researchfocus on the thin film coated field,.The film-forming block water oxygen barrier layer made the FOLED devices slimmer, longer life, superior mechanical properties.The main content of the thesis includes:First of all, I introduced the basic structure, material,working principle,failure mechanismsand facing problems of the OLED_s.Second, According to the measurement principle of calcium electrical test method,wedesigned and built the test system. And then, through software we can get the different calciumfilm conductivities at different time. According to the formula, we calculated the thin film ofwater oxygen transmission rate （WVTR） value.Thirdly, I summed up several OLED_s encapsulation methods, encapsulation technology,encapsulation structures. I select the organic-inorganic laminated package structure,filmpackaging materials（PDMS NOA63ZrO₂Al₂O₃）,thin film deposition techniques（atomic layerdeposition spin coating） to complete the experiment. I designed the organic-inorganic laminatedfilm encapsulation structure, combing the different materials together. At the same time, Iproduced theNOA63-ZrO₂，Alq₃-Al₂O₃laminate encapsulation structure, and measured theirWVTR respectively. The WVTR of the NOA-ZrO₂encapsulation film is as lower as9.0×10^-5g/m²/day. The WVTR of the thinner and lighter Alq₃-Al₂O₃encapsulation film is8.1×10^-4g/m²/day。Finally, the best structure of package will be applied to the organic light emitting diode,and to test the luminance decay curve, to predict the half-life of the organic device.