Development of Nanofluidic Thermoelectric Devices Using Two-Dimensional Materials

在透射电子显微镜下，我们已经固化了悬浮二维材料纳米孔制造的核心技术。具体来说，我们演示了从亚纳米到5纳米的孔隙铣削，显示了孔隙尺寸的可控性。提出了一种多重钻井工艺，并进行了测试，显示出出色的空间分辨率。对于每个钻孔，孔径可以控制在一纳米内。通过在稍微不同的位置重复这个过程，可以精确地雕刻出所需的孔隙形状。利用这种方法，我们创造了亚5纳米的高圆度孔。同时，我们构建了通过纳米孔芯片测量离子电流的流动系统，热源温度控制器，热电评价电流计。纳米孔膜可以精确控制储层的温度。另一方面，建立了基于泊松-能斯特-普朗克方程和纳维-斯托克斯方程的理论模型来预测系统的热电性能。结果表明，当特征双电层厚度接近孔隙半径时，功率密度达到最大值。这将指导我们的实验设计，选择合适的溶液条件。

We have solidified the core technique for nanopore fabrication on suspended two-dimensional materials under transmission electron microscopy. Specifically, we demonstrated pore milling from sub-nanometer to 5 nanometers, showing the controllability of the pore dimension. A multiple drilling process is proposed and tested showing outstanding spacial resolution. For each drilling the pore size can be controlled within one nanometer. By repeating the process at slightly different locations, the desired pore shape can be precisely sculpted. Using this method, we have created sub-5 nanometer pores with high circularity. In the meanwhile, we have constructed the flow system for ionic current measurements through nanopore chips, temperature controllers for heat source and purchased current meters for thermoelectric evaluations. The temperature in the reservoirs separated by the nanopore membrane can be precisely controlled. On the other hand, a theoretical model based on the Poisson-Nernst-Planck and Navier-Stokes equations has been constructed to predict thermoelectric performance of our system. It is shown that the power density reaches the maximum as the characteristic electric double layer thickness becomes close to the pore radius. This will guide our experimental design by selecting suitable solution conditions.