Electronic Absorption Spectra and Third-Order Nonlinear Optical Property of Dinaphtho[2,3-b:2’,3’-d]Thiophene-5,7,12,13- Tetraone (DNTTRA) and Its Phenyldiazenyl Derivatives: DFT Calculations

Ziran Chen,Hongping Li,Zhanrong He,Yuan Li,Yujin Zhang,Yonghua Guan

doi:10.4236/cc.2020.84005

Ziran Chen, Hongping Li + Show 4 more

Open Access

https://doi.org/10.4236/cc.2020.84005

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Abstract

Third-order nonlinear optical (NLO) materials have broad application prospects in high-density data storage, optical computer, modern laser technology, and other high-tech industries. The structures and frequencies of Dinaphtho[2,3-b:2’,3’-d]thiophene-5,7,12,13-tetraone (DNTTRA) and its 36 derivatives containing azobenzene were calculated by using density functional theory B3LYP and M06-2X methods at 6-311++g(d, p) level, respectively. Besides, the atomic charges of natural bond orbitals (NBO) were analyzed. The frontier orbitals and electron absorption spectra of A-G5 molecule were calculated by TD-DFT (TD-B3LYP/6-311++g(d, p) and TD-M06-2X/6-311++g(d, p)). The NLO properties were calculated by effective finite field FF method and self-compiled program. The results show that 36 molecules of these six series are D-π-A-π-D structures. The third-order NLO coefficients γ (second-order hyperpolarizability) of the D series molecules are the largest among the six series, reaching 107 atomic units (10-33 esu) of order of magnitude, showing good third-order NLO properties. Last, the third-order NLO properties of the azobenzene ring can be improved by introducing strong electron donor groups (e.g. -N(CH3)2 or -NHCH3) in the azobenzene ring, so that the third-order NLO materials with good performance can be obtained.

Highlights

Third-order nonlinear optical (NLO) materials have the characteristics of fast nonlinear optical response, large nonlinear polarizability, wide response band, high optical damage domain value, excellent flexibility, good chemical and thermal stability, and are easy to modify molecular structure
The structures and frequencies of Dinaphtho[2,3-b:2’,3’-d]thiophene-5,7,12,13-tetraone (DNTTRA) and its 36 derivatives containing azobenzene were calculated by using density functional theory B3LYP and M06-2X methods at 6-311++g(d, p) level, respectively
It can be predicted that the derivatives of azobenzene at 1.8 sites, 1.11 sites and 4.8 sites of DNTTRA molecule have less NLO properties than those of azobenzene at 2.9 sites, 3.9 sites, and 2.10 sites respectively

Summary

Introduction

Third-order nonlinear optical (NLO) materials have the characteristics of fast nonlinear optical response, large nonlinear polarizability, wide response band, high optical damage domain value, excellent flexibility, good chemical and thermal stability, and are easy to modify molecular structure. The large π conjugated parent structure would interact with the azo group after conjugated bridging the electron donor of phenyl, which can further enhance the delocalization of the electron, and can be designed as an organic electron transport material These structural molecules belong to D-π-A-π-D type organic molecules, and their chemical modification can improve the nonlinear optical properties of the molecules. We further studied the introduction of -OH, -OCH3, -NH2, -NHCH3, -N(CH3) into the para position of azobenzene ring It provides a theoretical reference for the further design and synthesis of the third-order nonlinear optical materials containing DNTTRA with excellent properties

Computational Details

Structures

Charge Analysis

Frontier Orbitals and Electron Absorption Spectra

Third-Order NLO Properties

Conclusion