Quantum Transport in Metalporphyrins. An ab initio Green's function approach to nanosensors design

TL;DR

This study uses ab initio Green's function methods to analyze electron transport in metal-porphyrin complexes, revealing their potential for nanosensor applications based on conductance properties.

Contribution

It introduces a Green's function approach to evaluate transport in metal-porphyrins, highlighting their suitability for nanosensor design and emphasizing the importance of spin considerations.

Findings

Fe(II) and Fe(III) porphyrins show high conductance at low bias.

Conductance decreases from Mn to Zn in the series.

Spin-unrestricted calculations are crucial for accurate results.

Abstract

An ab initio Green's function study of the electron transport properties of the selected metal-porphyrin complexes has been performed. Transmission spectra and current-voltage dependence have been calculated for the porphyrin molecule located between gold electrodes in the presence of interaction with metal atoms, which are most common in biochemistry (Fe(II), Fe(III), Mn(II), and Zn(II)). It was shown that the estimated Fermi level almost coincides with the LUMO level of Fe(II)-porphyrin and Fe(III)-porphyrin, resulting in significant conductance at small voltage biases. Conductance of Mn(II)-porphyrin and Zn(II)-porphyrin are much lower, and decrease from Mn to Zn. It was confirmed that performing spin-unrestricted calculations is essential to account splitting of the original molecular orbitals levels. Preformed calculations demonstrate the principal possibility of experimental realization of porphyrin based nanosensors.