Manipulating connectivity in random nanowire networks to create evolutionary materials and devices

Summary form only given. Nanowire networks (NWNs) are promising candidates for a range of material and device applications. Although much is known about the percolation behaviour of nanowire systems especially in polymer composites, the inherent connectivity in high density NWNs is not at all understood. Such networks are comprised of wires that are well connected but individual wires are frequently separated by surface passivation layers that control conduction. We begin by visualising the connectivity in NWNs and show that the voltage, spatial and thickness dependences can be understood in terms of a distribution of junction properties. We introduce a universal scaling relationship that is a fundamental property of NWNs and show it is consistent with the presence of locally connected regions or pockets within the network that ultimately lead to conduction. We demonstrate that network connectivity evolves in response to an applied electric field to create materials whose conductivity can be arbitrarily controlled. This intrinsic property of NWNs can be further modulated by the changing the wire coating or surface passivation to create families of evolutionary materials and devices that exhibit novel behaviours, i.e. their properties are non-static but rather evolve and adapt in response to external stimuli.