fig3

Figure 3. Crystallization of RP, DJ, and ACI phase 2D OIHP single crystals with cooling HX-based precursor method. (A) Schematic illustration of procedure to grow single crystals and (B) Optical image of RP phase BA₂Pb(Br_xI_1-x)₄ single crystals. Reprinted with permission from ref.^[31]: Copyright 2023, Royal Society of Chemistry. (C) Crystal structures of (DGA)PbI₄ and (D) Schematic and optical images of DJ phase DGA₂PbI₄ single crystals. Reprinted with permission from ref.^[25]: Copyright 2022, Wiley-VCH GmbH. (E) 2D bilayered crystal structures and (F) Photographs of GAMA₂Pb₂I₇ single crystals. Reprinted with permission from ref.^[27]: Copyright 2023, Elsevier.