Optical and NLO properties of zigzag carbon nanobelt compounds

Abstract

• Photophysical properties of CNBs were firstly studied. • The electron transition properties of CNBs were assigned. • The relation between substitutions and photophysical properties was established. • CNBs that introduce substituents from the perspective of breaking centrosymmetric may become potential second-order NLO materials with excellent performance. Zigzag carbon nanobelts (CNBs) attracted great attention from researchers with their potential applications in materials science and supramolecular chemistry. Photophysical properties of the reported CNB and five new designed substituted CNBs are investigated with the aid of density functional theory. Studies show that different substituents have different effects on the electronic structure, electronic transition and first hyperpolarizability. The introduction of electron donors and electron acceptors in a way like CNB 6 is an feasible way to obtain the smallest band gap and cause obvious charge separation in FMOs, and the introduction of different substituents makes the low-energy absorption band produce a significant red shift, and the insertion of substituents from the perspective of breaking centrosymmetric is the most effective method to enhance second-order NLO properties. In view of strong second-order NLO response of CNBs 5 and 6 , they may have the probability to be candidates used as excellent second-order NLO materials. Photophysical properties of the studied CNBs were studied with the help of the DFT calculations.