Investigation of SERS and Electron Transport Properties of Oligomer Phenylacetyne-3 Trapped in Gold Junctions.

Ziyu Liu,Jihui Zhang,Yujin Zhang,Muwafag Osman Adam Balila,Wei Hu,Tingting Hu

doi:10.3390/nano12030571

Abstract

Molecular junctions hold great potential for future microelectronics and attract people’s attention. Here, we used density functional theory calculations (DFT) to investigate the surface-enhanced Raman spectroscopy (SERS) and electron transport properties of fully π-conjugated oligomers (phenylacetylene)-3 (OPE-3) trapped in gold junctions. The effects of charge injection, an applied electric field, and molecular deformation are considered. We found that a new Raman peak located at around 1400 cm−1 appears after the injection of a charge, which agrees well with the experiment. The external electric field and configurational deformation hardly affect the Raman spectra, indicating that the electronic rather than the geometrical structure determines the Raman response. Nonequilibrium Green’s function (NEGF) calculations show that both the rotation of the benzene groups and an increased electrode distance largely reduced the conductivity of the studied molecular junctions. The present investigations provide valuable information on the effect of charging, electric field, and deformation on the SERS and conductivity of molecular junctions, helping the development of molecular devices.

Highlights

Accepted: January 2022The last years have witnessed the rapid development of molecular junctions and a wide variety of functional molecule devices have been proposed [1,2,3,4,5,6]
The geometries of the of the oligomer phenylene acetylene-3 (OPE-3) molecule were optimized after charges of −
At 2200 cm−1, there is splitting with an increasing of OPE-3 molecular junctions as future semiconductors, we studied the dependence of the electric field

Summary

Introduction

Accepted: January 2022The last years have witnessed the rapid development of molecular junctions and a wide variety of functional molecule devices (diodes, resistors, switches, sensors, LEDs, etc.) have been proposed [1,2,3,4,5,6]. Considering the OPE-3 molecule connected with an Au electrode via Au–S bond, here, we focus only on the electric field along the junction.

Results

Conclusion