Analysis of a dinitro-based molecular device

Abstract

A proposed dinitro device, Au-(2′-nitro-4-ethynylphenyl-4′-ethynylphenyl-5′-nitro-1-benzene thiolate)-Au is analyzed using a combination of density functional and Green function theories complemented with information from theoretical and experimental studies of a similar nitroamino device, Au-(2′-amino-4-ethynylphenyl-4′-ethynylphenyl-5′-nitro-1-benzenethiolate)-Au. The dinitro compound might also perform as a molecular memory but with different characteristics than those of the nitroamino, showing well-defined charge states; however, the neutral charge state of the nitroamino presents well-defined resonant tunneling characteristics and a larger intrinsic dipole moment. Density of states, transmission functions, and current–voltage characteristics for the neutral, anion, and dianion of the two molecules are compared. The effect of the bias potential is explicitly considered in the calculations as well as the effect of the contacts and the spin states of the open shell systems. The theoretical results for the training molecule are in good agreement with experiment. It is concluded that observed negative differential resistance is due mainly to charge effects combined in less degree with resonant tunneling intrinsic to single molecules.

Tuning of Organic Reversible Switching via Self‐Assembled Supramolecular Structures

“…This would lead to an increase in the off-state current and consequently a decrease in the on/off ratio to 100, which mimics the characteristics of present-day switching devices based on donor±acceptor groups. [22] In the I±V characteristics of Rose Bengal/PDDA structures, the off-state leakage current was much lower, and the on-state current much higher, than the respective currents in both spin-cast and Rose Bengal/PAH devices. The results show that just by changing the polycation in the supramolecular matrix, the on/off ratio can be tuned from 100 (for PAH) to 10 5 (for PDDA).…”

Ab initio analysis of electron currents in thioalkanes

“…One of the most studied types of molecules is alkanethiol [8, 12, 16 -20], because they can easily be chemisorbed (covalently bonded) to a gold surface through the S-Au bond in liquid phase, making a robust and mechanically stable attachment of a self-assembled molecular monolayer (SAM) [21][22][23][24]. This process allows accessing electrically one of the ends of the molecules; the other end is much more difficult and several alternatives have been performed.…”

Three-Terminal Devices to Examine Single-Molecule Conductance Switching

“…One suggested switching mechanism that has both motivated molecular design and been the focus of intense theoretical analysis is reduction of functional groups on the molecule [5]. Polaron formation is one way of potentially stabilizing this reduction [6].…”