Insights into vibrational and electronic properties of (6,6)-phenyl-C61-butyric acid methyl ester (PCBM) chemical bonding with (CuO)n clusters: a DFT study

Abstract

Density functional theory (DFT) was used to study the electronic and vibrational properties of the chemical bond between the [6,6]-phenyl-C61-Butyric acid methyl ester (PCBM) and (CuO)n clusters. After chemical adsorption, the HOMO orbitals of PCBM primarily shifted towards (CuO)n, leading to a noticeable reduction in the band gap. Similarly, the bond established is responsible for the spatial redistribution of boundary orbitals, mainly towards the clusters. In addition, the orbital analysis revealed that the primary contributions to the chemical bond originated from the Cu atoms. The PCBM Raman intensity shows a meaningful enhancement consequence of the chemical bond established with the clusters. In addition, new normal modes of PCBM are observed in the Raman activity spectrum after the chemical adsorption.