Oxidation-induced phase transformations of hybrid tin bromide single crystals enable the occurrence of second-harmonic generation

Abstract

Phase transformations of tin halide hybrid materials have played an important role in the formations of structural diversity and optoelectronic versatility due to the oxidability and instability from Sn2+ to...

Oxidation-Induced Dissolution Recrystallization Structural Transformation Strategy Enhanced Nonlinear Optical Effect of Hybrid Chiral Tin Bromide Single Crystals

“…A band gap value of approximately 2.60 eV is shown in the inset of Figure d, which is comparable to the value of the previously reported Sn­(IV) halide (2.64 eV). In line with the earlier study, the band gap of the Sn­(IV) material after DRST is smaller than that of the Sn­(II) material . As opposed to their enantiomers, S -2-mpip­[SnBr 3 ]Br and S -2-mpipSnBr 6 have band gaps of about 2.89 and 2.62 eV, respectively, while rac -2-mpip­[SnBr 3 ]Br has a band gap of around 2.55 eV.…”

“…R / S -2-mpip­[SnBr 3 ]­Br were crystallized under atmospheric conditions using the cooling crystallization method to produce colorless rod-like single crystals. Based on previously reported redox potential, H 3 PO 2 was added in a 5:1 ratio, which caused the yellow solution to change into a colorless, clear solution to inhibit the oxidation of Sn 2+ and Br – in the HBr solution. The heating temperature was maintained at 70 °C for half an hour to ensure that the starting materials were completely dissolved.…”

“…For this special SHG source, the octahedral tin halide hybrid material exhibits a very strong response to external disturbances. 31 Therefore, this theory can explain why the low-distortion Sn(IV)-based R-2-mpipSnBr 6 has stronger SHG properties.…”

“…39,40 The Sn 3d5/2 orbital binding energy of the R-2-mpipSnBr 6 sample was found to be 487.6 eV, as shown in Figure S8e, which is larger than that of R- In line with the earlier study, the band gap of the Sn(IV) material after DRST is smaller than that of the Sn(II) material. 31 3e, the Br 4p atomic orbitals make up the majority of the CBM for R-2-mpipSnBr 6 , while the Sn 5s and Br 4p orbitals make up the majority of the VBM. In line with the distinctions between Sn(II) and Sn(IV) type materials, it appears that the oxidation of Sn 2+ ions produces a significant alteration in the configuration of Sn 5s orbitals.…”

Thermal/Water-Induced Phase Transformation and Photoluminescence of Hybrid Manganese(II)-Based Chloride Single Crystals

“…Previously, most of the research focused on lead (Pb) metal halides. − However, the most serious issue lies in the toxicity of Pb. It is urgent to develop environmental-friendly lead-free metal halides with low-toxicity elements, such as copper (Cu), − tin (Sn), − antimony (Sb), , and manganese (Mn). − Among lead-free metal halides, Mn­(II)-based metal halides with a d 5 configuration that possesses the d–d transition exhibit outstanding optical characteristics. − Currently, Mn­(II)-based hybrid halides have attracted much interest due to their unique luminescent color and directly observed luminescent conversion. As we all know, Mn 2+ ions with tetrahedral coordination, in which each Mn 2+ is coordinated with four halogen (X) anions to form an [MnX 4 ] 2– tetrahedral unit, exhibit green emission due to the weak ligand/crystal field strength around Mn 2+ ions. − On the contrary, Mn 2+ ions with octahedral coordination, where each Mn is coordinated with six halogen anions to form an [MnX 6 ] 4– octahedral unit, exhibit red emission due to the strong ligand/crystal field strength surrounding Mn 2+ ions. ,− Interestingly, the coordination environment of Mn 2+ ions can be adjusted between the octahedron and tetrahedron by certain methods, such as temperature, humidity, and pressure, which leads to the variations of luminescent color of Mn­(II)-based hybrid halides. , A reversible conversion between the green emission of (C 5 H 8 N 2 ) 2 MnCl 4 (1-ethylimidazole) and red emission of C 5 H 8 N 2 (MnCl 2 ) x Cl y was demonstrated by Fu et al Zheng et al found an interesting luminescent conversion between green-emitting TMAMnCl 3 and red-emitting TMA 2 MnCl 4 (TMA = tetramethylammonium) that can be achieved by adding corresponding raw MnCl 2 or TMACl precursors .…”