Enhanced optical nonlinearities in push-pull organic systems with polyenic-mesoionic ring mixed bridges

Donor–acceptor diethynylsilane oligomers: A second‐order nonlinear optical material

“…The overall trend predicted at the PBE1PBE/6‐31G(d)//B3LYP/6‐31G(d) level of calculation is shown in Figure 4(a). β mol decreases with increasing BLA values, as expected for conjugated polymers 87, 88. For molecules I to IV , the NLO response is quite sensitive to the structural changes induced by the substituents, showing a quadratic increase with the respective decrease of the BLA parameter.…”

“…Several systems characterized in the literature having the strong acceptor dicyanovinyl display very low energy transitions for the charge transfer processes, which contribute to the increase in the nonlinear coefficients 94, 95. In addition, theoretical studies revealed large nonlinear responses for various polyenic and aniline derivatives with the acceptor dicyanovinyl group 2, 25, 87, 88, 96, 97. Several experimental and theoretical studies have shown that the magnitude of the first hyperpolarizability of organic molecules is associated with lower values of the HOMO–LUMO gap 2, 3, 24, 56, 57, 96–99.…”

“…b mol decreases with increasing BLA values, as expected for conjugated polymers. 87,88 For molecules I to IV, the NLO response is quite sensitive to the structural changes induced by the substituents, showing a quadratic increase with the respective decrease of the BLA parameter. This behavior was smoothed for molecules V-VII.…”

“…94,95 In addition, theoretical studies revealed large nonlinear responses for various polyenic and aniline derivatives with the acceptor dicyanovinyl group. 2,25,87,88,96,97 Several experimental and theoretical studies have shown that the magnitude of the first hyperpolarizability of organic molecules is associated with lower values of the HOMO-LUMO gap. 2,3,24,56,57,[96][97][98][99] As found in this work, the DFT results showed that introduction of the D-A pairs decreases the ground-state dipole moment (l) of the PDES derivatives in comparison with the nonsubstituted oligomer (see Table 4).…”

Nonlinear Optical Properties of Halogenated Aniline Oligomers

“…The dimensionality of the system, molecular asymmetry, size and nature of the linker between the donor and acceptor groups, donor-acceptor (D-A) pair electronic strength, and molecular conformation are parameters that influence the  and  magnitudes of the organic-based materials, as has been demonstrated by experimental and theoretical studies (Machado et al, 2008(Machado et al, , 2011aChampagne & Kirtman, 2001; Kanis et al, 1994;Brédas et al, 1994). Recently, DFT calculation for aniline showed that larger hyperpolarizabilities in quintet state than the singlet state raises the possibility of spin multiplicity control of nonlinear responses (Deshmukh et al, 2012).…”