Organic-Inorganic Hybrid Tin Halide Single Crystals with Sulfhydryl and Hydroxyl Groups: Formation, Optical Properties, and Stability.

Lead (Pb)-free halide hybrid materials have received a great deal of attention because of their potential in optoelectronic applications. However, heteroatom-based amine lead-free tin halide hybrid single crystals have not been well investigated yet. Detailed synthetic processes, growth, crystal structures, and stability of (ACH 2 CH 2 NH 3 ) 2 SnBr 6 (A = OH or SH) and (BCH 2 CH 2 NH 3 ) 2 SnI 4 (B = I or SH) single crystals were investigated. Interestingly, (IH 3 NCH 2 CH 2 SSCH 2 CH 2 NH 3 ) 2 HPO 3 exhibited orange-red photoluminescence (PL) at about 620 nm with an average PL lifetime of about 912 ns. (HSCH 2 CH 2 NH 3 ) 2 SnI 4 single crystals exhibited a PL peak at 620 nm with an average PL lifetime of about 0.607 ns. More importantly, (HSCH 2 CH 2 NH 3 ) 2 SnI 4 single crystals exhibited reversible red-black color transformations when exposed to a H 3 PO 2 solution and an ambient atmosphere, which was attributed to oxidation from Sn 2+ to Sn 4+ , rather than from I - to I 3 - (I 2 ). The intriguing characteristics should provide guidance for further optoelectronic applications of these Pb-free halide hybrid materials.