Carvalho Fernandes Deisy C, Lynch Dylan, Berry Vikas
Department of Chemical Engineering, University of Illinois at Chicago, Chicago, IL, USA.
Sci Rep. 2020 Jul 9;10(1):11373. doi: 10.1038/s41598-020-68288-5.
Designing 3D printed micro-architectures using electronic materials with well-understood electronic transport within such structures will potentially lead to accessible device fabrication for 'on-demand' applications. Here we show controlled nozzle-extrusion based 3D printing of a commercially available nano-composite of graphene/polylactic acid, enabling the fabrication of a tensile gauge functioning via the readjustment of the electron-tunneling barrier width between conductive graphene-centers. The electronic transport in the graphene/polymer 3D printed structure exhibited the Fowler Nordheim mechanism with a tunneling width of 0.79-0.95 nm and graphene centers having a carrier concentration of 2.66 × 10/cm. Furthermore, a mechanical strain that increases the electron-tunneling width between graphene nanostructures (~ 38 nm) by only 0.19 Ǻ reduces the electron flux by 1e/s/nm (from 18.51 to 19.51 e/s/nm) through the polylactic acid junctions in the 3D-printed heterostructure. This corresponds to a sensitivity of 2.59 Ω/Ω%, which compares well with other tensile gauges. We envision that the proposed electron-tunneling model for conductive 3D-printed structures with thermal expansion and external strain will lead to an evolution in the design of next-generation of 'on-demand' printed electronic and electromechanical devices.
利用在这种结构中具有充分理解的电子传输特性的电子材料来设计3D打印微结构，可能会为“按需”应用带来便捷的器件制造方法。在此，我们展示了基于可控喷嘴挤出的3D打印市售石墨烯/聚乳酸纳米复合材料，能够制造一种通过调整导电石墨烯中心之间的电子隧穿势垒宽度来发挥作用的拉伸应变计。石墨烯/聚合物3D打印结构中的电子传输表现出Fowler Nordheim机制，隧穿宽度为0.79 - 0.95纳米，石墨烯中心的载流子浓度为2.66×10/cm。此外，仅使石墨烯纳米结构之间的电子隧穿宽度（约38纳米）增加0.19埃的机械应变，会使通过3D打印异质结构中聚乳酸结的电子通量降低1e/s/nm（从18.51降至19.51 e/s/nm）。这对应于2.59 Ω/Ω%的灵敏度，与其他拉伸应变计相比具有优势。我们设想，所提出的用于具有热膨胀和外部应变的导电3D打印结构的电子隧穿模型，将引领下一代“按需”打印电子和机电设备设计的发展。
