Diverse Transport Behaviors in Cyclo[18]carbon-Based Molecular Devices

Abstract

Scientists have been trying to synthesize ring-shaped pure carbon molecules for a half century. A breakthrough was made recently, and cyclo[18]carbon (C 18 ) was produced successfully by bonding an 18-atom ring of carbon. Because of its potential application in molecular devices, it is natural and timely to study the transport behaviors of C 18 . Here we report the electron transport properties of the C 18 -ring connected to various electrodes, including 1D carbon chain, 2D graphene, and 3D silver electrodes, using densityfunctional theory combined with the nonequilibrium Green's function technique. Diverse transport behaviors are found for the C 18 molecular devices, including an Ohmic characteristic, a quasi Schottky feature, and a current-limiting function. The origin and mechanism of unique nonlinear I−V characteristics are investigated by the transmission pathway, transmission spectra, density of states, and molecular frontier orbital theory. This study provides a theoretical guide for exploring the next-generation molecular devices based on this newcomer to the family of carbon allotropes.

TAO-DFT investigation of electronic properties of linear and cyclic carbon chains

“…Consequently, the E ST values of l-CC[n]/c-CC [n] reported in the present study can provide insight into the singlet-fission phenomenon. For other relevant applications, it is worth mentioning that the electronic transport properties of c-CC [18]-based molecular devices have been recently studied 38 .…”

“…On the other hand, cyclic carbon chains (for brevity, denoted as c-CC[n] (see Fig. 1b)), which are the monocyclic isomers of linear carbon chains, have also attracted considerable attention in recent years [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] . Note that c-CC [n] (where the carbon atoms are also sp-hybridized) are hypothesized to be the building blocks of fullerenes in the initial stages of growth 21 .…”

“…Among them, c-CC [18] has recently been synthesized 26 , and some of the electronic properties of c-CC [18] have been reported. There are also a few theoretical studies on the electronic properties and applications of c-CC [18] and other cyclic carbon chains 22,[27][28][29][30][31][32][33][34][35][36][37][38] . For example, c-CC [18] has been found to possess electron-acceptor properties, and can be dubbed as the smallest all-carbon electron acceptor 28 .…”

Giant Switching Effect and Spintronic Transport Properties in Cyclo[18]carbon‐Based Molecular Devices

“…[ 9–17 ] Currently, C 18 composed of 18 carbon atoms by sp‐hybridization has been demonstrated to exhibit ohmic and quasi Schottky features, as well as current limiting ability in molecular devices. [ 18 ] Furthermore, C 18 may display excellent conductivity in molecular devices owing to its extensive π electron delocalization. [ 19,20 ] For example, Xu and Wu [ 21 ] indicated that C 18 ‐based molecular devices exhibited the switching effect and negative differential resistance (NDR) effect.…”

Vibrational Spectra and Molecular Vibrational Behaviors of All‐Carboatomic Rings, cyclo[18]carbon and Its Analogues

“…Nevertheless, people still have not been able to obtain its stable separation product. With the confirmation of experimental evidence, a lot of theoretical efforts have been made to study properties of the cyclo[18]carbon from many aspects, including tunneling effect, [22] electron transfer, [23,24] surface coupling, [25] and so on [26–28] . Lately, we have also carried out a series of theoretical investigations on electron delocalization, aromaticity, electronic spectrum, optical nonlinearity, and intermolecular interaction of the cyclo[18]carbon [29–31] …”