DFT molecular simulations for static, dynamic and solvent-dependent nonlinear optical properties of triphenylamine-carbazole-based organic dyes with D-D-A framework

Abstract

Nonlinear optical (NLO) materials are vital for advancing cutting-edge optoelectronic technology. Herein, triphenylamine-carbazole-based organic dyes with a D-D-A framework are quantum chemically designed with acceptor modifications, and their geometric, electronic, static, dynamic, and solvent-dependent NLO properties are explored using density functional theory (DFT) simulations. The IEFPCM model is employed to investigate the solvent effect on the NLO properties of proposed compounds (BSA-1 to BSA-9). Interestingly, the dipole moment (μtot), average linear polarizability (αtot), and first hyperpolarizability (βtot) were determined for all proposed compounds in gas phase and water (ε = 78.36), DMSO (ε = 46.83), methanol (ε = 32.61), tetrahydrofuran (ε = 7.43), chloroform (ε = 4.71), and benzene (ε = 2.27) solvents. Natural population analysis (NPA), transition density matrix (TDM), UV–Vis investigation, frontier molecular orbital (FMO), and topological analysis (MEP, ELF, and LOL) were carried out to explain the NLO findings. The topological study suggests that BSA and BSA-1 to BSA-9 are chemically active and may have NLO implications. Moreover, the findings demonstrate that BSA-9 is the most promising second-order NLO candidate because of the highest λmax (418.60 nm) in dichloromethane (DMF) and the lowest energy gap (1.49 eV) among all the derivatives. It was found that BSA-2 and BSA-9 demonstrated the giant static αo (7.26 × 102) and βo (9.91 × 104) values among the proposed compounds for use in a wide range of solvent-dependent NLO applications. The solvent effect on NLO in all proposed compounds is noticeable, especially in BSA-9, which exhibited βo = 1.89 × 105 in benzene, 2.80 × 105 in THF, 3.21 × 105 in methanol, 3.25 × 105 in DMSO and 3.28 × 105 in water. Furthermore, Electro-optical Pockels effect (EOPE) β(-ω,ω,0) and the second harmonic generation (SHG) β(-2ω,ω,ω) results computed at ω = 532 nm (0.0856 au) and ω = 1064 nm (0.0428 au) frequencies confirm that all proposed compounds are excellent NLO candidates and should be targeted for future static, frequency-dependent and solvent-dependent NLO applications.