An Jae Seok, Jang Ha Jun, Park Cheol Young, Youn Hongseok, Lee Jong Ho, Heo Gi-Seok, Choi Bum Ho, Lee Choong Hun
J Nanosci Nanotechnol. 2015 Oct;15(10):8199-204. doi: 10.1166/jnn.2015.11279.
Inorganic/organic hybrid thin film encapsulation layers consist of a thin Al2O3 layer together with polymer material. We have investigated optical properties of thin film encapsulation layers for top-emission flexible organic light-emitting diodes. The transmittance of hybrid thin film encapsulation layers and the electroluminescent spectrum of organic light-emitting diodes that were passivated by hybrid organic/inorganic thin film encapsulation layers were also examined as a function of the thickness of inorganic Al203 and monomer layers. The number of interference peaks, their intensity, and their positions in the visible range can be controlled by varying the thickness of inorganic Al2O3 layer. On the other hand, changing the thickness of monomer layer had a negligible effect on the optical properties. We also verified that there is a trade-off between transparency in the visible range and the permeation of water vapor in hybrid thin film encapsulation layers. As the number of dyads decreased, optical transparency improved while the water vapor permeation barrier was degraded. Our study suggests that, in top-emission organic light-emitting diodes, the thickness of each thin film encapsulation layer, in particular that of the inorganic layer, and the number of dyads should be controlled for highly efficient top-emission flexible organic light-emitting diodes.
无机/有机混合薄膜封装层由一层薄的Al2O3层和聚合物材料组成。我们研究了用于顶部发射柔性有机发光二极管的薄膜封装层的光学性质。还研究了混合薄膜封装层的透过率以及被混合有机/无机薄膜封装层钝化的有机发光二极管的电致发光光谱，作为无机Al2O3和单体层厚度的函数。通过改变无机Al2O3层的厚度，可以控制干涉峰的数量、强度及其在可见光范围内的位置。另一方面，改变单体层的厚度对光学性质的影响可以忽略不计。我们还证实，在混合薄膜封装层中，可见光范围内的透明度与水蒸气渗透之间存在权衡。随着二元组数量的减少，光学透明度提高，而水蒸气渗透阻挡层性能下降。我们的研究表明，在顶部发射有机发光二极管中，为了实现高效的顶部发射柔性有机发光二极管，应控制每个薄膜封装层的厚度，特别是无机层的厚度以及二元组的数量。
