Figure 4.

a) Photograph of a single crystal of Cs₂AgBiBr₆. Reproduced with permission.^{[ 76 ]} Copyright 2016, American Chemical Society. b) Schematic of antisolvent vapor assisted crystallization of Cs₃Cu₂I₅ single crystal. Reproduced with permission.^{[ 61 ]} Copyright 2018, Wiley‐VCH. c) Schematic representation of the synthesis of Cs₃Sb₂I₉ nanoplatelets and Cs₃Sb₂I₉ nanorods. (ODE = 1‐octadecene, OnA = octanoic acid, OAm = oleylamine.) Reproduced with permission.^{[ 96 ]} Copyright 2017, Wiley‐VCH. d) Schematic illustration of the reaction system for LARP technique. Reproduced with permission.^{[ 80 ]} Copyright 2017, American Chemical Society. e) Schematic view of the synthesis process of the ultrathin A₃Bi₂I₉ films (A = Cs⁺ or MA⁺). Reproduced with permission.^{[ 95 ]} Copyright 2017, Wiley‐VCH. f) Schematic illustration of the vapor‐based synthesis of Cs₂TiBr₆ halide perovskite thin film. Vapor‐deposited CsBr thin film before annealing (film I), after 12 h annealing (film II), and after 24 h annealing (film III) at 200 °C. Reproduced with permission.^{[ 97 ]} Copyright 2018, Cell Press.