(Invited) Electrical Properties of Vapor-Deposited Organic Semiconductor Nanowires By Conductive Atomic Force Microscopy

Abstract

Understanding how organic semiconductors self-assemble and create nanoscale morphologies is integral for the development of organic electronics. In particular, one-dimensional (1D) molecular nanostructures are of interest because of their unique optoelectronic properties as well as their potential role in fundamental charge transport research. Here, we investigate four small molecules (TpCPD, TpDCF, AcCPD, and AcDCF) possessing anisotropic, non-planar structures and large dipole moments, and establish robust algorithms to control their molecular self-assembly via physical vapor deposition. We find that only molecules containing the fused ring system form 1D nanowires due to the stronger van der Waals associations of the long, planar acenaphthene moieties. We examine the kinetics of self-assembly of AcDCF and create diverse 1D morphologies. Finally, using conductive AFM (c-AFM), we show that 1D wires support higher current densities relative to randomly-oriented clusters lacking long-range order through space-charge limited current (SCLC) measurements. Figure 1