Adsorption of 4,4″-Diamino-p-Terphenyl on Cu(001): A First-Principles Study

Chang-Tian Wang,Shixuan Du,Yan-Fang Zhang

doi:10.3390/surfaces4010005

Abstract

Single-molecular devices show remarkable potential for applications in downscale electronic devices. The adsorption behavior of a molecule on a metal surface is of great importance from both fundamental and technological points of view. Herein, based on first-principles calculations, the adsorption of a 4,4″-diamino-p-terphenyl (DAT) molecule on a Cu(001) surface has been systematically explored. The most stable configuration is the DAT molecule lying flat with a rotation angle of 13° relative to the [100] surface direction. It was found that the adsorption sites of benzene rings and nitrogen atoms in the DAT molecule have important influences on the stability of the adsorption configuration. Electron density differences analysis shows that the electrons accumulate at the DAT-Cu(001) interface. The density of states projected on a DAT molecule of DAT/Cu(001) exhibits a metallic character, while the freestanding ones are semiconducting, indicating a strong interaction between the DAT molecule and the Cu(001) surface in the most stable adsorption configuration. These results provide useful information for tuning the properties and functions of DAT molecules, and may offer useful insights for other organic molecule/surface systems.

Highlights

Molecule–metal hybrid systems have attracted much attention in modern surface science and technology for their potential applications in heterogeneous catalysis, molecular electronics, photovoltaics, and light-emitting diodes [1,2,3,4,5,6,7,8]
The first-principles calculations are based on the density functional theory (DFT) with the projector augmented wave (PAW) method [34] implemented in the Vienna ab initio simulation package (VASP) code [35]
The adsorption of a 4,4 -diamino-p-terphenyl molecule on the Cu(001) surface has been investigated by first-principles calculations

Summary

Introduction

Molecule–metal hybrid systems have attracted much attention in modern surface science and technology for their potential applications in heterogeneous catalysis, molecular electronics, photovoltaics, and light-emitting diodes [1,2,3,4,5,6,7,8]. The simple yet elegant 4,4 -diaminop-terphenyl (DAT) molecule is composed of three non-planar benzene rings and two amino groups, which is small but complete for evaluating the absorption mechanism of a 3D amino-functionalized organic molecule It represents one of the most promising and versatile classes owing to its unique properties as a monomer of a conjugated polymer, polyazomethine, and has been applied to polymer light-emitting diodes by vapor deposition polymerization [24]. The calculated electron density difference and density of states show a strong interaction with a large electron accumulation between the DAT molecule and the Cu(001) surface These results provide a comprehensive understanding for molecular adsorptions on metal surfaces

Computational Methods

Electronic Properties

Conclusions