Department of Industrial Engineering, University of Pittsburgh, Pittsburgh, PA 15261, United States of America.
Nanotechnology. 2018 Oct 19;29(42):42LT01. doi: 10.1088/1361-6528/aad671. Epub 2018 Jul 27.
Transparent polymer substrates have recently received increased attention for various flexible optoelectronic devices. Optoelectronic applications such as solar cells and light emitting-diodes would benefit from substrates with both high transparency and high haze, which increase how much light scatters into or out of the underlying photoactive layers. In this letter, we demonstrate a new flexible nanograss plastic substrate that displays the highest combination of transparency and haze in the literature for polyethylene terephthalate (PET). As opposed to other nanostructures that increase haze at the expense of transparency, our nanograss demonstrates the potential to improve both haze and transparency. Furthermore, the monolithic nanograss may be fabricated in a facile scalable maskless reactive ion etching process without the need for additional lithography or synthesis of nanostructures. Our 9 μm height nanograss sample exhibits a transparency and haze of 92.4% and 89.4%, respectively, and our 34 μm height nanograss displays a transparency and haze of 91.0% and 97.1%, respectively. We also performed durability experiments that demonstrate these nanostructured PET substrates are robust from bending and show similar transmission and haze values after 5000 cycles of bending.
透明聚合物衬底最近因其在各种柔性光电设备中的应用而受到越来越多的关注。光电应用，如太阳能电池和发光二极管，将受益于具有高透明度和高雾度的衬底，这增加了光散射到或离开底层光活性层的程度。在这封信中，我们展示了一种新的柔性纳米草塑料衬底，其在聚对苯二甲酸乙二醇酯（PET）中显示了文献中最高的透明度和雾度组合。与其他以牺牲透明度为代价来提高雾度的纳米结构不同，我们的纳米草具有提高雾度和透明度的潜力。此外，整体纳米草可以通过简单的无掩模反应离子刻蚀工艺制造，而不需要额外的光刻或纳米结构合成。我们的 9μm 高纳米草样品分别显示出 92.4%和 89.4%的透明度和雾度，而我们的 34μm 高纳米草分别显示出 91.0%和 97.1%的透明度和雾度。我们还进行了耐久性实验，证明这些纳米结构的 PET 衬底具有很强的弯曲稳定性，并且在经过 5000 次弯曲循环后，它们的传输率和雾度值仍保持相似。
