A Quantum Chemical Screening of Two Imidazole-Chalcone Hybrid Ligands and Their Pd, Pt and Zn Complexes for Charge Transport and Nonlinear Optical (NLO) Properties: A DFT Study

Abstract

A quantum chemical screening of two imidazole-based chalcone ligands: 2-[1-(3-(1H-imidazol-1-yl)propylimino)-3-(phenylallyl)]phenol and 2-[1-(3-(1Himidazol-1-yl)propylimino)-3-4-nitrophenylallyl]phenol (hereinafter referred to as HL1 and HL2 respectively) and their Pd, Pt and Zn chelates for charge transport and nonlinear optical (NLO) properties, is reported via dispersioncorrected density functional theory (DFT-D3) and time-dependent DFT (TD-DFT) methods. From our results, Pd and Pt complexes have been observed to show excellent hole-transport properties, owing to their very small reorganization energies. The light extraction efficiency of the HL1-Pt complex was deduced to be particularly impressive, thus suitable for the manufacture of hole transport layer in violet light emitting diodes (LEDs). Moreover, redox potentials and chemical stability studies have enabled us to validate the greater stability in moisture (towards oxidation), of HL2 complexes compared to their HL1 counterparts. The first and second hyperpolarizabilities of both ligands and their complexes have been found to be outstandingly higher than those of the push-pull prototypical, para-nitroaniline by factors of up to 12 in the case of HL2. These compounds, with the exception of the HL2-Pt complex, are thus interesting candidates having wide transparency tradeoffs for NLO efficiency in the manufacture of optoelectronic and photonic devices capable of second and third-order NLO response. Finally, metal chelation has been established to enhance the NLO response of all the chalcone-based imidazole ligands investigated as a result of metal-ligand charge transfer and ligand-

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

“…Small reorganization (λ electron/hole ) energy values indicate better charge transport rates and mobility, which give rise to good charge transport properties for the materials [39]. Results from Table 2 show that the increasing trend in the λ electron values is as follows: A smaller IP a value means easier hole injection ability for the OLED materials, while a larger EA a value facilitates electron injection [8,53]. Table 2 shows that INH13 (7.129 eV) has the lowest IP a value, while INH8 (1.578 eV) has the highest EA a value.…”

“…Reorganization energy is partitioned into internal and external reorganization energies [8]. Te internal reorganization energy refers to the energy change of the system caused by the structural relaxation after the gain or loss of electrons, while the external reorganization energy describes the change in electronic polarization of the surrounding compounds [38,39].…”

“…Low molecular weight organic compounds have recently become popular in the optoelectronic industry due to their potential applications in organic light-emitting diodes (OLEDs) [1,2], organic solar cells (OSCs) [3], organic feld efect transistors (OFETs) [4], and nonlinear optics (NGOs) [5][6][7]. NLO and OLED technologies have received a lot of attention due to their applications in optical and fat-panel displays [8]. Owing to its potential applications in modern computers, optical data storage, communications, laser technology, and photonics, NLO materials have attracted the curiosity of many researchers [9].…”

A Tetracyanobutadiene Spirobifluorene: Synthesis, Enantiomeric Resolution and Chiroptical Properties

“…Therefore, the analysis of the charge transfer in the three structures seems to be essential. In literature, frontier molecular orbitals (FMOs) and natural transitions orbitals (NTOs) have been employed to study and visualize the ICT [34–36] . Even some studies have shown a correlation between the HOMO‐LUMO gap and hyperpolarizabilities and ICT [36–38] …”

“…In literature, frontier molecular orbitals (FMOs) and natural transitions orbitals (NTOs) have been employed to study and visualize the ICT. [34][35][36] Even some studies have shown a correlation between the HOMO-LUMO gap and hyperpolarizabilities and ICT. [36][37][38] Frontier molecular orbitals and HOMO-LUMO gap for the three conformers were collected in the Supporting Information and NTOs for the first and second dominant electronic transitions were visualized at the CAM-B3LYP/6-31G(d,p) (Figure 5).…”