Length‐Independent Charge Transport in Chimeric Molecular Wires

A first-principles study of phthalocyanine-based multifunctional spintronic molecular devices

In this study, using the first-principles method, we theoretically investigated the spin-dependent transport properties of a phthalocyanine (Pc) molecule, which is sandwiched between two zigzag-edged graphene nanoribbon (zGNR) electrodes. Owing to the spatial symmetry of the Pc molecule and spin splitting of zGNRs around Fermi energy, perfect spin filtering behavior is observed in designed molecular junctions. Meanwhile, the spin of electrons allowed through the device is right opposite to the spin polarization of zGNR electrodes. Further studies show that the spin filtering performance can be largely modulated by insetting different transition metal atoms (TM = Mn or Cr) into the central Pc molecule, and changing the spin-polarized direction of the TM atom leads to the spin filtering direction inversion. More intriguingly, the antiparallel magnetic configuration of two zGNR electrodes gives rise to the control of the conducting channel by bias polarization, which eventually leads to remarkable spin rectifying and giant magnetoresistance behaviors in transition metal phthalocyanine (TMPc) molecular junctions. The corresponding mechanisms are revealed by an analysis of spin-resolved transmission spectra, molecular projected self-consistent Hamiltonian and a projected density of states. These results are helpful in the design of TMPc-based multifunctional spin molecular devices.

Assessing the Role of Intermolecular Interactions in a Perylene-Based Nanowire Using First-Principles Many-Body Perturbation Theory

We present a first-principles many-body perturbation theory study of the role of intermolecular coupling in the optoelectronic properties of a one-dimensional (1D) π-stacked nanowire composed of perylene-3,4,9,10-tetracarboxylic diimide molecules on a DNA-like backbone. We determine that strong intermolecular electronic coupling results in large bandwidths and low carrier effective masses, suggesting a high-electron mobility material. Additionally, by including the role of finite-temperature phonons on optical absorption via a newly presented approach, we predict that the optical absorption spectrum  is significantly altered from that at zero temperature due to allowed indirect transitions, while the exciton delocalization and binding energy, a measure of intermolecular electronic interactions, remains constant. Overall, our studies indicate that strong intermolecular coupling can dominate the optoelectronic properties of π-conjugated 1D systems even at room temperature.

Can Molecular Quantum Interference Effect Transistors Survive Vibration?

Quantum interference in cross-conjugated molecules can be utilized to construct molecular quantum interference effect transistors. However, whether its application can be achieved depends on the survivability of the quantum interference under real conditions such as nuclear vibration. We use two simulation methods to investigate the effects of nuclear vibration on quantum interference in a meta-linked benzene system. The simulation results suggest that the quantum interference is robust against nuclear vibration not only in the steady state but also in its transient dynamics, and thus the molecular quantum interference effect transistors can be realized.

A controllable mechanistic transition of charge transfer in helical peptides: from hopping to superexchange

A controllable mechanistic transition of charge transfer in helical peptides is demonstrated as a direct result of side-bridge gating.