Table 1.

Summary of the prepared halide double perovskites

Materials	Morphology	Synthetic method	References
Cs2NaMCl6 (M=Am, Bk, Tl, Bi, Lu, etc.)	Powder or single crystal	Evaporating HCl solution to dryness, or heating anhydrous chlorides, or precipitating from cold HCl solution, or growing crystals from dilute HCl solution by cooling evaporation	[41–47]
Cs2AgBiCl6	Powder	Melt crystallization Precipitation from heated acid solution	[48, 49]
	Nanocrystal	Hot injection Antisolvent recrystallization	[50, 51]
Cs2AgBiBr6	Powder	Melt crystallization Precipitation from heated acid solution	[48]
	Single crystal	Cooling crystallization	[52, 54, 55]
	Nanocrystal	Hot injection Antisolvent recrystallization	[50, 51, 56]
Cs2(Ag1−aBi1−b)TlxBr6	Single crystal	Cooling crystallization	[57]
Cs2Ag(Bi1−xMx)Br6 (M=In, Sb)	Single crystal	Melt crystallization	[58]
Cs2AgBiI6	Nanocrystal	Antisolvent recrystallization Anion exchange	[50, 51]
Cs2AgInCl6	Single crystal Powder	Cooling crystallization Precipitating from cold HCl solution	[59–61]
Mn-doped Cs2AgInCl6	Microcrystal	Hot injection	[62]
Cs2NaBiI6	Microcrystal	Hydrothermal method	[64]
Cs2SnI6	Microcrystal Nanocrystal	Hot injection	[74–76]
Bi-doped Cs2SnCl6	Single crystal	Cooling crystallization	[77]
Cs2PdBr6	Single crystal	Cooling crystallization	[78]
	Nanocrystal	Antisolvent recrystallization	[79]
Cs2PdI6	Nanocrystal	Anion exchange	[79]
A2TiBr6 (A=K, Rb, Cs)	Powder	Molten salt	[80]
Cs2TiIxBr6−x (x = 0, 2, 4, 6)	Powder	Melt crystallization	[81]
(MA)2KBiCl6	Powder	Evaporating HCl solution to dryness	[38]
(MA)2TlBiBr6	Single crystal	Hydrothermal method	[82]
(MA)2AgBiBr6	Powder	Evaporating HBr solution to dryness	[83]
(MA)2AgSbI6	Powder	Melt crystallization	[84]
(MA)2AgBiI6	Powder	Melt crystallization	[85]
(MA)2KGdCl6 (MA)2KYCl6	Powder	Evaporating HCl solution to dryness	[86]
(MA)2AgInBr6	Single crystal	MAPbBr3-induced crystallization	[87]
(MA)2SnI6	Powder	Mixed iodides	[88]