Enhancement of one- and two-photon absorption and visualization of intramolecular charge transfer of pyrenyl-contained derivatives

Jia Wei; Yuanzuo Li; Peng Song; Yanhui Yang; Fengcai Ma

doi:10.1016/j.saa.2020.118897

Enhancement of one- and two-photon absorption and visualization of intramolecular charge transfer of pyrenyl-contained derivatives

Spectrochim Acta A Mol Biomol Spectrosc. 2021 Jan 15:245:118897. doi: 10.1016/j.saa.2020.118897. Epub 2020 Sep 2.

Authors

Jia Wei¹, Yuanzuo Li², Peng Song³, Yanhui Yang⁴, Fengcai Ma³

Affiliations

¹ College of Science, Northeast Forestry University, Harbin 150040, Heilongjiang, China.
² College of Science, Northeast Forestry University, Harbin 150040, Heilongjiang, China. Electronic address: yzli@nefu.edu.cn.
³ Department of Physics, Liaoning University, Shenyang 110036, Liaoning, China.
⁴ Institute of Advanced Synthesis, School of Chemistry and Molecular Engineering, Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, Nanjing 211816, Jiangsu, China; School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 639798, Singapore.

PMID: 32937267
DOI: 10.1016/j.saa.2020.118897

Abstract

To further improve the pyrenyl-contained derivatives two-photon absorption (TPA) and third-order nonlinear optical (NLO) properties, three steps of optimization are employed based on experimental molecule PCVS-B: heteroatomic substitution, exchanging the position of double bonds and adding a branch. The contributions of π electrons to localized orbital locators and Mayer bond orders (LOL-π and I_AB^π) show that the second step can enhance the chemical interaction between pyrenyl and the branched-chain. Two visual methods of charge density difference (CDD) and transition density matrix (TDM) are combined to intuitively analyze the intramolecular charge transfer (ICT) process of one (two) photon absorption; results show that both following two steps can increase the degree of ICT on the conjugated plane of the pyrenyl. The sum over state (SOS) model was used to find out the dominant two-photon transition process. The difference between the dipole moments obtained by the McRae equation is applied to the three-state model, revealing the inherent law of the second static hyperpolarizability.

Keywords: DFT; ICT process; Second hyperpolarizability; TDM; TPA cross-section.