Influence of A-site cation on the thermal stability of metal halide perovskite polycrystalline films

Figures & data

Figure 1. SEM images of the MAPbBr₃ polycrystalline films with different thermal annealing conditions: (a) without annealing; (b) annealed at 70°C for 10 min; (c) annealed at 120°C for 10 min; (d) annealed at 180°C for 10 min; (e) annealed at 180°C for 30 min; and (f) annealed at 230°C for 30 min.

Figure 2. SEM images of the CsPbBr₃ polycrystalline films with different thermal annealing conditions: (a) without annealing; (b) annealed at 70°C for 10 min; (c) annealed at 120°C for 10 min; (d) annealed at 180°C for 10 min; (e) annealed at 180°C for 30 min; and (f) annealed at 230°C for 30 min.

Figure 3. XRD patterns of (a) MAPbBr₃ and (b) CsPbBr₃ polycrystalline films with different thermal annealing conditions. (c) Magnified XRD pattern of the MAPbBr₃ films annealed at 230°C for 30 min (bottom) and calculated pattern of PbBr₂ (top) [30].

Table 1. XRD peak positions of the MAPbBr₃ polycrystalline films depending on the thermal annealing condition.

	(100)	(110)	(200)	(210)
70°C 10 min	15.02	21.26	30.20	33.86
180°C 30 min	15.02	n.a.	30.22	n.a.
230°C 30 min	n.a.	n.a.	n.a.	n.a.

Note: n.a.: not available because the film was decomposed.

Table 2. XRD peak positions of the CsPbBr₃ polycrystalline films depending on the thermal annealing condition.

	(101)	(121)	(202)	(321)
70°C 10 min	15.26	21.58	30.78	37.90
180°C 30 min	15.18	21.64	30.82	37.86
230°C 30 min	15.16	21.72	30.82	37.84

Table 3. Lattice parameters of the MAPbBr₃ and CsPbBr₃ polycrystalline films depending on the thermal annealing condition.

		Lattice parameter (Å)
	Annealing condition	a = b = c
MAPbBr3	70°C 10 min	5.891
	180°C 30 min	5.891
	230°C 30 min	n.a.
		a	b	c
CsPbBr3	70°C 10 min	8.208	11.669	8.195
	180°C 30 min	8.231	11.545	8.257
	230°C 30 min	8.253	11.447	8.257

Note: n.a.: not available because the film was decomposed.

Figure 4. Steady-state PL spectra of the (a) MAPbBr₃ and (b) CsPbBr₃ polycrystalline films after annealing at 70°C, 120°C, or 180°C for 10 min.

Figure 5. PL lifetime curves of the (a) MAPbBr₃ and (b) CsPbBr₃ polycrystalline films after annealing at 70°C, 120°C, or 180°C for 10 min.

Table 4. Short PL lifetime (), long PL lifetime (), and average lifetime () of the MAPbBr₃ and CsPbBr₃ polycrystalline films depending on T_ANN ( is a statistical measure that evaluates the goodness of fit (the closer is to 1, the higher the fitting quality).

	Annealing condition	(ns)	f1 (%)	(ns)	f2 (%)		(ns)
MAPbBr3	70°C 10 min	34.8	41	114.0	59	1.01	81.5
	120°C 10 min	30.0	73	101.0	27	0.89	69.3
	180°C 10 min	7.0	95	59.3	5	0.49	9.6
CsPbBr3	70°C 10 min	6.5	55	39.3	45	0.44	21.1
	120°C 10 min	6.7	58	38.9	42	0.38	20.2
	180°C 10 min	5.7	57	33.1	43	0.40	17.4

M. Lumbreras, J. Protas, S. Jebbari, G.J. Dirksen, and J. Schoonman, Solid State Ionics 20, 295–304 (1986). doi: 10.1016/0167-2738(86)90049-4

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