Theoretical Investigation of the Nonlinear Optical and Charge Transport Properties of N-(4-Methoxybenzylidene) Isonicotinohydrazone and Some of Its Derivatives: A DFT and TD-DFT Study

Abstract

Here, we report the findings from a study on the charge transport and nonlinear optical (NLO) properties of N-(4-methoxybenzylidene) isonicotinohydrazone (INH) and some of its derivatives named INH1-INH15. The density functional theory (DFT) approach was used for ground state computations at the B3LYP-D/6-311G (d,p) level of theory, while the time-dependent density functional theory (TD-DFT) was carried out at the CAM-B3LYP/6-311G (d,p) level. The results show that the energy gaps of all the studied compounds range from 3.933 to 4.645 eV. INH3 and INH4 have the lowest electron and hole reorganization energies (i.e., 0.409 and 0.634 eV, respectively) and can thus be classified as moderate electron and hole-carrying materials for organic light-emitting diode (OLED) applications. TD-DFT computations demonstrate that an extension of the conjugation (in INH2 and INH3) increases the oscillator strength, improving the NLO response. According to the NLO data, INH2 and INH3 have higher static isotropic polarizabilities (38.509 and 37.986 × 10−24 esu, respectively) and second hyperpolarizabilities (54.440 and 57.598 × 10−36 esu, respectively), while INH4 and INH13 have higher first hyperpolarizability values (11.944 and 10.939 × 10−30 esu, respectively). The results reveal that INH derivatives with different groups are viable alternatives for OLED and NLO applications.