Charge Separation and Dissipation in Molecular Wires under a Light Radiation

TL;DR

This paper presents a dynamic quantum analysis of charge separation and dissipation in molecular wires under light radiation, revealing how Coulomb interactions, light intensity, and effective masses influence charge behavior.

Contribution

It introduces a time-dependent non-equilibrium Green's function approach to study charge dynamics in molecular wires, advancing beyond static and classical models.

Findings

Charge separation depends on Coulomb interaction and light intensity.

Electron/hole wave packet behavior is influenced by effective masses.

Charge dissipation is characterized in open nano systems.

Abstract

Photo-induced charge separation in nanowires or molecular wires had been studied in previous experiments and simulations. Most researches deal with the carrier diffusions with the classical phenomenological models, or the static energy levels by quantum mechanics calculations. Here we give a dynamic quantum investigation on the charge separation and dissipation in molecule wires. The method is based on the time-dependent non-equilibrium Green's function theory. Polyacetylene chain and poly-phenylene are used as model systems with a tight-binding Hamiltonian and the wide band limit approximation in this study. A light pulse with the energy larger than the band gap is radiated on the system. The evolution and dissipation of the non-equilibrium carriers in the open nano systems are studied. With an external electric potentials or impurity atoms, the charge separation is observed. Our calculations show that the separation behaviors of the electron/hole wave packets are related to the Coulomb interaction, light intensity and the effective masses of electron/hole in the molecular wire.