Density Functional Theory Investigation of Nonlinear Optical Properties of T-Graphene Quantum Dots

Abstract

Using density functional theory calculations, we have analyzed nonlinear optical properties of a series of T-graphene quantum dots differing in their shape and size. Electronic polarizability and first-order and second-order hyperpolarizability of these systems are investigated and shed light on their stability and electronic properties. Negative cohesive energy shows that they are energetically stable. The effect of size and incident frequency on their nonlinear responses are comprehensively discussed. Most of the systems exhibit a strong NLO response, and it is enhanced in the presence of an external field. All these systems show absorption maximum ranging from UV to visible window. Overall, this theoretical framework highlighted the nonlinear optical properties of T-graphene quantum dots that may provide valuable information in designing potential NLO materials.

Confinement Effects of a Noble Gas Dimer Inside a Fullerene Cage: Can It Be Used as an Acceptor in a DSSC?

“…To explore the relationship between the efficiency of the dye molecules and their non-linear optical (NLO) properties, the isotropic polarizability of the dyes has been calculated. The response of any system when it is subjected to an external electric field is characterized by the study of NLO properties of that system (Deb et al, 2020 ). In case of dye D1, the isotropic polarizability is found to be 574.045 au, while for the dye D1@He 2 the value increases to 577.945 au.…”

Doping and Surface Modification of Carbon Quantum Dots for Enhanced Functionalities and Related Applications

“…Nonlinear optical (NLO) properties of CQDs have been unraveled theoretically by DFT studies. [ 128,147 ] The stability and electronic properties of these systems have been studied by implementing electronic polarizability as well as the first‐order and second‐order hyperpolarizability calculations. A negative value of cohesive energy implies the stability of the system and the type of doping whether in‐plane/out‐of‐plane.…”

Investigation of Optical Properties for N and F Doped Triangular Shaped Carbon Molecules 

“…All molecules are stable structures for the positive frequency (Table 1). The cohesive energy per atom (E p ) in Table 1 is calculated using the following formula 43 :…”

“…Absorption spectra of N-doping 3 and 4 have three absorption peaks, which are assigned to the π-π* transition of the conjugated ole n, and n-π* transitions of a class of unsaturated double bonds containing heteroatoms 44 . Besides, absorption spectrum of pure carbon 0 has been calculated with ZINDO/S 43 , with the peak position 267nm. That with b3lyp/6-31g(d,p) is about 250nm which is shorter than that with ZINDO/S, which is similar to reference 45 .…”