(259i) Detailed Characterization and Fabrication of 3D Printed Graphene/Polymer Structures for Heterojunction-Devices with MoS2 and Other 2D Nanomaterials

Designing 3D printed micro-architectures using electronic materials with well-defined electronic structures will potentially lead to accessible device fabrication for ‘on-demand’ applications. Here we show gelation of 2D nanomaterial mixtures, their 3D gel-printing, and the resultant device’s characterization for six different concentration of MoS₂/graphene (MoS₂:rGO) (100:0, 10:90,30:70, 50:50, 70:30, 90:10) and graphene/BN (BN:rGO) (50:50) alloys. Rheology studies show the viscoelastic properties of the gels, including viscosity and yield stress. The shear-thinning behavior was engineered to provide the ability of fabricate 3D printed device via an aligned controlled nozzle-extrusion based modified 3D printer, enabling the fabrication of composite electrodes. The 3D printed devices structure was arrested by lyophilization induced water removal. These electronic, structural and mechanical properties were investigated. The ordered graphitic region with sp² hybridized carbon atoms in the graphene sheets is in the order of 8.28 ±0.23 nm. The temperature-dependent electronic transport of 3D printed electrodes structures exhibits a transport-barrier of 16.24 meV and a tunneling width of 0.45 nm (Fowler Nordheim electron tunneling) with graphene centers having a carrier concentration of 1.7x10¹¹/cm^-2. By modifying the graphene/MoS₂ concentration, the Young’s Modulus of the structure can be controlled between 6 and 16 kPa. We envision that the proposed 3D-printing of gels of nanomaterial will lead to an evolution in the design of next-generation of ‘on-demand’ printed electronic and electromechanical devices.