Kwon Jeong Hyun, Jeong Eun Gyo, Jeon Yongmin, Kim Do-Geun, Lee Seunghun, Choi Kyung Cheol
Advanced Nano-Surface Department , Korea Institute of Materials Science , Changwon , Gyeongnam 51508 , Republic of Korea.
School of Electrical Engineering , KAIST , Daejeon 34141 , Republic of Korea.
ACS Appl Mater Interfaces. 2019 Jan 23;11(3):3251-3261. doi: 10.1021/acsami.8b11930. Epub 2019 Jan 8.
The lack of a transparent, flexible, and reliable encapsulation layer for organic-based devices makes it difficult to commercialize wearable, transparent, flexible displays. The reliability of organic-based devices sensitive to water vapor and oxygen must be guaranteed through an additional encapsulation layer for the luminance efficiency and lifetime. Especially, one of the major difficulties in current and future OLED applications has been the absence of thin-film encapsulation with superior barrier performance, mechanical flexibility, and water-resistant properties. In this work, we fabricated highly water-resistant, impermeable, and flexible inorganic/organic multilayers with optimized AlO and functional organic layers. The key properties of the fabricated multilayers were compared according to the thickness and functionality of the inorganic and organic layers. Improvement of the barrier performance is mainly attributed to the optimized thickness of the AlO films, and is additionally due to the increased lag time and effective surface planarization effects caused by the use of micrometer-thick organic layers. As a result, the 3-dyad multilayer structure composed of 60 nm-thick AlO layers deposited at 70 °C and 2-μm-thick silane-based inorganic/organic hybrid polymer (silamer) layers with layered silica exhibited the lowest WVTR value of 1.11 × 10 g/m/day in storage conditions of 30 °C/90% relative humidity. In addition, the multibarrier exhibited good mechanical stability through the use of alternating stacks of brittle inorganic and soft organic layers, without showing a large increase in the WVTR after bending tests. In addition, silamer layers improved the environmental stability of the AlO ALD film. The silamer layer coated on the AlO film effectively worked as a protective layer against harsh environments. The effective contact at the interface of AlO/silamer makes the barrier structure more impermeable and corrosion-resistant. In this study, we not only demonstrated an optimized multilayer based on functional organic layers but also provided a methodology for designing a wearable encapsulation applicable to wearable organic electronics.
缺乏用于有机基器件的透明、灵活且可靠的封装层使得可穿戴、透明、柔性显示器难以实现商业化。对于对水蒸气和氧气敏感的有机基器件，必须通过额外的封装层来保证其可靠性，以实现发光效率和使用寿命。特别是，当前和未来OLED应用中的一个主要难题一直是缺乏具有优异阻隔性能、机械柔韧性和防水性能的薄膜封装。在这项工作中，我们制备了具有优化的AlO和功能有机层的高防水、不透水且柔性的无机/有机多层膜。根据无机层和有机层的厚度及功能，对制备的多层膜的关键性能进行了比较。阻隔性能的提高主要归因于AlO薄膜的优化厚度，此外还归因于使用微米级有机层导致的滞后时间增加和有效的表面平坦化效应。结果，由在70°C下沉积的60nm厚的AlO层和具有层状二氧化硅的2μm厚的硅烷基金属有机杂化聚合物（硅聚物）层组成的3-二元多层结构在30°C/90%相对湿度的储存条件下表现出最低的水汽透过率（WVTR）值，为1.11×10 g/m²/天。此外，通过使用脆性无机层和柔软有机层的交替堆叠，多阻隔层表现出良好的机械稳定性，在弯曲测试后WVTR没有大幅增加。此外，硅聚物层提高了AlO原子层沉积（ALD）膜的环境稳定性。涂覆在AlO膜上的硅聚物层有效地起到了抵御恶劣环境的保护层作用。AlO/硅聚物界面处的有效接触使阻隔结构更不透水且耐腐蚀。在本研究中，我们不仅展示了基于功能有机层的优化多层膜，还提供了一种设计适用于可穿戴有机电子器件的可穿戴封装的方法。
