Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University (NanjingTech), 30 South Puzhu Road, Nanjing 211816, People's Republic of China.
Nanotechnology. 2017 Apr 21;28(16):164001. doi: 10.1088/1361-6528/aa6133. Epub 2017 Mar 22.
Transparent and flexible devices based on two-dimensional (2D) materials hold great potential for many electronic/optoelectronic applications. The direct and fast thickness identification of 2D materials on transparent substrates is therefore an essential step in such applications, but remains challenging. Here, we present a simple, rapid and reliable optical method to identify the thickness of 2D nanosheets on transparent substrates, such as polydimethylsiloxane, glass, and coverslip. Under reflection and transmission light, 1-20L MoS and 1-14L WSe nanosheets can be reliably identified by measuring the optical contrast difference between the 2D nanosheets and substrates in color, red, green or blue channels. Meanwhile, the values of all the measured contrast differences as a function of layer number can be well fitted with the Boltzmann function, indicating the generalizability and reliability of our optical method. Our method will not only facilitate the fundamental study of the thickness-dependent properties of 2D nanosheets, but will also expand their potential applications in the field of flexible/transparent electronics and optoelectronics.
基于二维（2D）材料的透明和灵活器件在许多电子/光电子应用中具有巨大的潜力。因此，在这些应用中，直接快速识别透明衬底上的 2D 材料的厚度是必不可少的一步，但这仍然具有挑战性。在这里，我们提出了一种简单、快速和可靠的光学方法，用于识别透明衬底（如聚二甲基硅氧烷、玻璃和盖玻片）上 2D 纳米片的厚度。在反射光和透射光下，可以通过测量 2D 纳米片和衬底在颜色（红、绿或蓝通道）之间的光学对比度差异，可靠地识别 1-20L MoS 和 1-14L WSe 纳米片。同时，所有测量的对比度差异值随层数的变化可以很好地符合玻尔兹曼函数，表明我们的光学方法具有通用性和可靠性。我们的方法不仅将促进对 2D 纳米片厚度相关性质的基础研究，而且还将扩展它们在柔性/透明电子和光电子领域的潜在应用。
