A new type of organic–inorganic hybrid NLO-phore with large off-diagonal first hyperpolarizability tensors: a two-dimensional approach†
Abstract
We report a novel type of organic–inorganic hybrid material with rare two-dimensional nonlinear optical (NLO) properties. The density functional theory (DFT) calculations combined with the finite-field (FF) method show that the designed molecules (6,9 organo-derivatives of B10H14) could carry the characteristic NLO properties of both organic and inorganic materials. Interestingly, due to their unique V-shaped structures, they have large off-diagonal first hyperpolarizability tensors or nonlinear anisotropy, which is an advantage in their practical applications over conventional donor–π-acceptor (D–π-A) NLO-phores. The systematic substitutions of terminal donor/acceptor groups as well as the extension of π-conjugation along the V-shape in these derivatives have been evaluated to guide a purpose-oriented synthesis of NLO material. All the systems in the present study have been categorized into Set-I and Set-II with D–π-A–π-D and A–π-D–π-A configurations, respectively. These designed derivatives show large amplitudes of βz values. For example, systems 3N (6,9-[(NCPh–NO2)2]-B10H12) and 4N (6,9-[((NCPh)2-NO2)2]-B10H12) have βz amplitudes as large as 34.16 and 276.91 × 103 a.u. which are 380 and 3000 times larger than those of a typical NLO molecule of