20-State Molecular Switch in a Li@C₆₀ Complex

Abstract

A substantial potential advantage of industrial electric and thermoelectric devices utilizing endohedral metallofullerenes (EMFs) is their ability to accommodate metallic moieties inside their empty cavities. Experimental and theoretical studies have elucidated the merit of this extraordinary feature with respect to developing electrical conductance and thermopower. Published research studies have demonstrated multiple state molecular switches initiated with 4, 6, and 14 distinguished switching states. Through comprehensive theoretical investigations involving electronic structure and electric transport, we report 20 molecular switching states that can be statistically recognized employing the endohedral fullerene Li@C60 complex. We propose a switching technique that counts on the location of the alkali metal that encapsulates inside a fullerene cage. The 20 switching states correspond to the 20 hexagonal rings that the Li cation energetically prefers to reside close to. We demonstrate that the multiswitching feature of such molecular complexes can be controlled by taking advantage of the off-center displacement and charge transfer from the alkali metal to the C60 cage. The most energetically favorable optimization suggests 1.2–1.4 Å off-center displacement, and Mulliken, Hirshfeld, and Voronoi simulations articulate that the charge migrates from the Li cation to C60 fullerene; however, the amount of the charge transferred depends on the nature and location of the cation within the complex. We believe that the proposed work suggests a relevant step toward the practical application of molecular switches in organic materials.

Tuning quantum interference through molecular junctions formed from cross-linked OPE-3 dimers

“…Next we consider the electrical conductance when electrodes are connected to thiols 1 and 4 or 2 and 3. Since the 1-4 path includes ortho 'a'-'c' and ortho 'd'-'f', we To examine the above quantum interference predictions, we construct a Hu ¨ckel (i.e., tight binding, TB) Hamiltonian, [26][27][28][29][30][31][32][33][34][35][36][37] which captures the dependence of the conductance for the two cross-linked dimers on their connectivity to electrodes. The Hamiltonian matrix comprises of diagonal elements H jj = e j , which describe the energy e j of an electron on site j and nearest neighbour off-diagonal elements H ij , which describe hopping integrals between neighbouring sites l and j.…”

Three distinct conductance states in polycyclic aromatic hydrocarbon derivatives

“…We used a double-zeta plus polarization orbital basis set, norm-conserving pseudopotentials, the local density approximation (LDA) exchange-correlation functional, and an energy cutoff of 250 rydbergs to define the real space grid. We also computed the results using the generalized gradient approximation (GGA) and found that the resulting transmission functions were comparable [30][31][32][33] to those obtained using LDA. To simulate the likely contact configuration during a break-junction experiment, we used leads constructed from six layers of PAHs.…”

High Seebeck coefficient from isolated oligo-phenyl arrays on single layered graphene via stepwise assembly

“…In this study, it was shaped into a cone-shaped tip, and the tip retained its shape due to the formation of a ∼0.7 nm native oxide outer shell (GaOx) upon contact with air. 49,50 It has been proved that this type of tip can contact non-destructively with SAMs4, 8–52 and form Cu/Gr/SAMs/GaOx/EGaIn junction.…”

“…[7][8][9] The electric and thermoelectric properties of molecular junctions have been extensively investigated in recent years, both at the level of individual molecules [10][11][12][13] and self-assembled monolayers (SAMs). [14][15][16] These studies have predominantly focused on noble-metal substrates like gold, silver, and platinum, together with organic molecular backbones, with specific anchor groups, such as thiolate, [17][18][19] pyridine, fullerene, 20,21 and large p systems. 22,23 These anchor groups bind to a metallic substrate and facilitate the spontaneous formation of molecular layers on the substrate.…”