Crystalline Mixed Halide Halobismuthates and Their Induced Second Harmonic Generation

Abstract

Mixed halide coordination has been widely used to finely tune the properties of inorganic and inorganic− organic hybrid compounds, especially for emerging perovskites materials. Despite the increasing number of reports on preparation methods and the affected functionalities, the peculiar and precise role of the doping halogens in structural regulation of the crystals and the resulting variations on the basic properties remain to be addressed. Here, to shed light into the "black box", a new series of [NH 2 (CH 2 CH 3 ) 2 ] 3 Bi(Cl 1−x Br x ) 6 (x = 0, 0.135, 0.255, 0.385, 0.847, and 1) single crystals were grown from the mixed halide solvents by the temperature lowering method. The correlation between the inclusion amounts of Br in the final crystals with the halide concentrations in the precursors is discussed from different perspectives. The two kinds of halogens share the same position in the mixed halide system, with every crystallographically independent halide site possessing different halogen occupancies. The mixed halide coordination exhibits a regulated effect on the distortion of the anion octahedra. Optical absorption, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and the second harmonic generation (SHG) measurements have confirmed that, with increased Br inclusion, [NH 2 (CH 2 CH 3 ) 2 ] 3 Bi(Cl 1−x Br x ) 6 crystals exhibit a regulated effect on their bandgaps, thermal stabilities, and SHG capacities.

Shedding light on the nature of the catalytically active species in photocatalytic reactions using Bi2O3 semiconductor

“…The simplest form of the complex formed during the reaction might be a coordination of the bismuth (III) to the carbonyl donor group. However, the soft Lewis acid character and the halogenophilic properties of bismuth may result in the coordination with the bromine atom 31 , 32 . Based on these reports, direct interaction with the bromine atom could also be envisaged.…”

Photonics and Optoelectronics of 2D Metal‐Halide Perovskites

“…However, the nonlinear property such as second harmonic generation (SHG) has been rarely reported in emerging perovskite with form AMX 3 . Nevertheless, SHG‐based laser has been obtained from the interface of conventional perovskite films (LaAlO 3 /SrTiO 3 ) (Figure f), and in principle, it can be expected to yield SHG in these novel perovskite films for lasing by stacking different materials or crystalline mixing …”

Broad Photoluminescence and Second-Harmonic Generation in the Noncentrosymmetric Organic–Inorganic Hybrid Halide (C6H5(CH2)4NH3)4MX7·H2O (M = Bi, In, X = Br or I)

“…10,11 To date, only a few low-dimensional OIMHs have been reported to exhibit NLO conversion, demonstrating their potential in SHG; however, their SHG coefficients are relatively low, such as Cs 3 Pb 2 (CH 3 COO) 2 X 5 (X = Br and I), 12 [(CH 3 ) 2 CHNH 3 ]-G e I 3 , 1 3 N H ( C H 3 ) 3 S n C l 3 , NH(CH 3 ) 3 S n B r 3 , 1 4 [NH 2 (CH 2 CH 3 ) 2 ] 3 BiCl 6 , and [NH 2 (CH 2 CH 3 ) 2 ] 3 BiBr 6 . 15 Additionally, OIMHs are promising photoluminescent (PL) materials, as most of them show very broad light emission (with full width at half-maximum larger than 100 nm) when excited with ultraviolet light. This luminescence results from the soft lattice distortion of the material, resulting in selftrapped exciton emission (STE).…”