Semi-empirical infrared spectra simulation of pyrene-like molecules insight for simple analysis of functionalization graphene quantum dots

Abstract

The Infrared (IR) spectra usually assume the samples are 3D materials. Thus, it is difficult to identify functional groups in 2D materials at the edge and the center of the 2D surface. Therefore, it is crucial to introduce analysis methods that enable the investigation of 2D carbon materials such as graphene and its derivatives using IR spectra. This study calculates the infrared spectra of pyrene-like molecules as an insight for a simple analysis of graphene quantum dots using a semi-empirical method. These IR spectra were correlated to the electronic transition and charge distribution associated with functional groups. The IR spectra analysis focuses on comparing the pristine and functionalized molecule at the wavenumber 1400–2000 cm−1, especially to identify the C=C stretching mode and 3000–3500 cm−1 for C–H and OH stretching. Moreover, the determination of excitation spectra was carried out to analyze the electronic transition of the molecules in the ultraviolet–visible region (200–900 nm) calculated using ZINDO method. The investigation of the pyrene-like GQD permitted the identification of the edge and center surface functionalization in 2D carbon materials.