From C₄H₇N₂Ge_0.4Sn_0.6Br₃ to C₆H₁₁N₂Ge_0.4Sn_0.6Br₃: Effective Modulation of the Second Harmonic Generation Effect and Optical Band Gap by Planar π-Conjugated Organic Cation Size

Abstract

In the search for nonlinear optical (NLO) materials with excellent overall performance, we have devoted ourselves to organic−inorganic hybrids consisting of anionic groups containing stereochemically active lone-pair (SCALP) electron cations and organic planar π-conjugated group cations. Accordingly, in this paper, two novel organic−inorganic hybrid metal halides, C 4 H 7 N 2 Ge 0.4 Sn 0.6 Br 3 (I) and C 6 H 11 N 2 Ge 0.4 Sn 0.6 Br 3 (II), have been synthesized. The powder second-harmonic technique shows that both C 4 H 7 N 2 Ge 0.4 Sn 0.6 Br 3 and C 6 H 11 N 2 Ge 0.4 Sn 0.6 Br 3 have moderately strong second-order nonlinear optical effects, which are about 2.03 (I) and 1.16 (II) times that of KH 2 PO 4 (KDP), respectively. They also have different optical band gaps of 2.75 (I) and 2.88 eV (II) due to the different sizes of the organic cations, and their photoluminescent and thermal properties were also investigated. This work provides new structural insights for the design and modulation of organic−inorganic hybrid halide materials with multiple excellent optical properties.

Advancing nonlinear optics: discovery and characterization of new non-centrosymmetric phenazine-based halides

“…The role of π-conjugated organic groups has been extensively discussed, emphasizing their significance across all three compounds. 24,52,55,56 Furthermore, the heightened polarization of larger inorganic polyhedra contributes to the SHG effect, a phenomenon consistently supported by previous studies. 57–61 To quantify the distortion in the inorganic polyhedra, their dipole moments were calculated.…”

Passivation of Organic–Inorganic Hybrid Perovskite with Poly(lactic Acid) to Achieve Stable Red-Light Flexible Films

“…The diversity of organic cations and inorganic polyhedra endows low-dimensional OIHPs with structural tunability and various unique photophysical properties. − For example, Li et al improved the yellow-light quantum yield (QY) of zero dimension (0D) Sb-based perovskite from 0 to 79.57% by changing the spatial conjugation degree of organic molecules . Kang et al realized the adjustment of the optical band gap of organic–inorganic hybrid perovskite from 2.75 to 2.88 eV by changing the planar π-conjugated organic cation size . Liu et al used methylamine, formamidine, and aminoguanidine to regulate the interlayer distance of the crystal lattice and enhance the carrier transport rate.…”