Solution-phase processing of two-dimensional nanomaterials for printed and flexible electronics

Abstract

Two-dimensional (2D) materials have attracted a great deal of attention in recent years due to their superlative electronic, mechanical and optical properties, making them highly versatile building blocks for a range of applications. 2D materials can be produced from liquid-phase exfoliation (LPE) of their bulk parent solids in organic solvents and/or surfactants without chemical reactions, in which the input of energy to peel off 2D monolayers is provided by ultrasonication or shear mixing. The resulting dispersions are stable and highly processable, ideal for ink formulation and integration into printed electronic devices. In addition, LPE is a promising method for industrial scale production of 2D materials. This project aims to develop ink formulations based on 2D nanomaterials for printed electronics. Briefly, 2D nanosheets will be produced from LPE of layered bulk crystals. Thickness and lateral size sorting of nanosheets will be achieved from separation methods based on centrifugation.The monodisperse stable dispersions will be processed to give ink formulations suitable for inkjet printing technology. Different elements of electronic devices will be inkjet printed on flexible substrates, forming well-defined heterostructures: graphene as a conducting material for electrical contacts and interconnects, molibdenum disulfide as a semiconducting active channel, and hexagonal boron nitride as an insulator for dielectrics. These all-printed heterostructures can be integrated into field-effect transitor devices, which have emerged as versatile model electronic platforms for studying material properties. The possibility of integrating two or more 2D materials into well-defined structures opens up new paths for the creation of novel functional devices for optoelectronics, sensors, energy storage, and so forth.