curves for control-HaP, (b) low hysteresis of J-V curves for w/-PbI2-HaP, (c) ... on FTO. δ[100]h. PbI2 [001]t α[100]c δ[101]h α[110]c. -1.0 qxy (Å. -1. ) q z. (Å. -1. ).
Supplementary information for
Understanding how excess lead iodide precursor improves halide perovskite solar cell performance
Byung-wook Park et. al.
1
(a)
(b)
Film type Au
Thickness (nm)
PTAA
20 - 50
HaP
350 - 650
mp-TiO2
80 – 200
d-TiO2
40 – 60
FTO
600 - 660
~ 80
Supplementary Figure 1 – Side-by-side comparison of morphology (a) and atomic number (b) contrast of the device cross section. The characteristic thickness of the various layers was not affected by the presence of excess of PbI2 in the deposition solution.
2
Supplementary Figure 2 – Illustration of the fitting process to extract diffusion lengths.
3
25
25
a
b Current density [mA/cm ]
20 2
2
Current density [mA/cm ]
20
Revers Forward
15
10
Voc (V)
1.05
1.03
Jsc(mA/cm2)
22.53
22.51
Fill factor (%) 76.22 46.77 10.82
Efficiency (%) 17.98
5
Revers Forward
Control-HaP
0
Revers Forward
15
10
1.06
Voc (V)
1.10
Jsc(mA/cm2)
23.14 22.42
Fill factor (%) 77.27 80.86 Efficiency (%) 19.63 19.17
5
Revers Forward
w/-PbI2-HaP
0 0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
1.1
1.2
0.0
0.1
0.2
0.3
0.4
Potential [V]
22.7
0.8
22.2
EQE
0.4
Control-HaP w/PbI2-HaP 400
450
0.8
0.9
1.0
1.1
1.2
20
Control HaP w/-PbI2 HaP
16 14 12 10 8 6 4 2
0.0 350
0.7
18
mA/cm2
0.6
0.2
22
d
mA/cm2
The number of samples
c
0.6
Potential [V] 24
1.0
0.5
500
550
600
650
Wavelength [nm]
700
750
800
850
0 16.0
16.5
17.0
17.5
18.0
18.5
19.0
19.5
20.0
20.5
Solar cell efficiency [%]
Supplementary Figure 3. J-V curves for two representative HaP solar cells: (a) high hysteresis of J-V
curves for control-HaP, (b) low hysteresis of J-V curves for w/-PbI2-HaP, (c) External quantum efficiency for cells made with control- and w/-PbI2-HaP, and (d) Histogram of efficiencies for the
cells fabricated with and without excess PbI2. Details on the PV cell fabrication are given in the main text.
4
Supplementary Figure 4 – Side by side SE and EBIC images of cross-sections of cells with (a) Control-HaP and (b) w/PbI2-HaP. The paths of the line profiles are marked with thin blue horizontal lines with arrows. The EBIC signal distributions are summarized in (c) and (d), for the two samples, using the results from the (a) and (b) images, respectively.
5
α[300]c α[311]c α[220]c
α[310]c α[221]c
PbI2 [003]t
FTO
FTO
α[211]c
3.1
α[210]c δ[202]h
FTO δ[112]h
qz (Å-1)
α[200]c PbI2 [002]t α[111]c
α[110]c
FTO α[100]c
2.1
δ[101]h δ[201]h PbI2 [001]t
δ[002]h δ[100]h
0.1
-2.0
-1.0
0.0 qxy (Å-1)
δ[101]h
1.0
2.0
Supplementary Figure 5. Miller indexes on 2D GIWAXS pattern for FA cation-substituted HaP film
on FTO.
6
Ek = 11.6 keV
Penetration Depth (nm)
100
10
1 0.0
0.1
0.2
0.3
0.4
0.5
o
Incidence angle, i ( ) Supplementary Figure 6. X-ray penetration depth to α-FAPbI3 film with x-ray incidence angles which
were reported previously.1
7
a
B A
-FAPbI3 [100] -FAPbI3 [200]
Intensity [A. U.]
PbI2 [001]
PbI2 excess
Control sample 10
15
20
25
30
35
X-ray diffrection angle [2]
Supplementary Figure 7. Full (2θ range) XRD spectra for control-HaP and w/-PbI2-HaP films on
were done on a Rigaku D/MAX2500V/PC X-ray diffractometer bFTO. (XRD measurements PbI excess 2 2
Intensity [A. U.]
1
11.8
12.0
12.2
12.4
12.6
12.8
13.0
Control
13.2
13.4
12.0
Center 12.77725 12.85372
Area Peak 1: 210.15656 Peak 2: 211.0563
Center FWHM 12.7437 0.25172 12.80439 0.11217
FWHM 0.23873 0.1181
Height 692.1582 2003.76955
13.6
1
11.8
Area Peak 1: 207.09961 Peak 2: 296.58554
2
Intensity [A. U.]
PbI2 [001]h
at 40 kV, 200 mA with a Cu target.)
12.2
12.4
12.6
12.8
13.0
13.2
13.4
Height 666.13963 1501.33919
13.6
2
Intensity [A. U.]
PbI2 excess PbI excess 2
2 Area Peak 1: 1735.16897 Peak 2: 3011.67664
1
13.8
13.9
14.0
14.1
14.2
14.3
14.4
14.5
13.9
14.0
14.1
Area Peak 1: 2090.85529 Peak 2: 3589.83594
14.2
2
FWHM 0.2036 0.09152
Height 6800.04623 26254.88968
B
1
13.8
Center 14.18562 14.25265
14.6
2
Control Control
Intensity [A. U.]
HAP [100]c
c
14.3
14.4
14.5
Center 14.14002 14.19573
FWHM 0.20013 0.08493
Height 8335.87239 33726.02575
14.6
8
(b)
Control-HaP
α-FAPbI3 [100]c
(a)
o
i = 0.15
w/-PbI2-HaP
α-FAPbI3 [100]c
o
i = 0.15 o
i = 0.2
o
Intensity (a.u.)
i = 0.2
Intensity (a.u.)
o
i = 0.3
0
20
40
60
80
o
i = 0.3
0
100 120 140 160 180
20
60
α-FAPbI3 [100]c
(d)
100 120 140 160 180
α-FAPbI3 [100]c
Substrate
Substrate Control-HaP
PbI2 [001]t
(e)
80
Azimuthal angle ( )
Azimuthal angle ( )
(c)
40
o
o
o
i = 0.15
(f)
PbI2 [001]t
w/-PbI2-HaP o
o
i = 0.15
o
i = 0.2
i = 0.2
0
20
40
60
80
100 120 140 160 180 o
Azimuthal angle ( )
Intensity (a.u.)
Intensity (a.u.)
i = 0.3
o o
i = 0.3
0
20
40
60
80
100 120 140 160 180 o
Azimuthal angle ( )
Supplementary Figure 8. (a and b) One-dimensional (1D) patterns of α-HaP [100]c at qxy of 1.0/Å, (c
and d) schemes of texturing of crystal domains for control- and w/-PbI2-HaP, and (e and f) 1D patterns of PbI2 [001]t at qxy of 0.9/Å obtained from 2D-GIWAXS (Fig. 3).
9
Supplementary Figure 9. 2D GIWAXS images of as-prepared w/PbI2-HaP film observed over 6 s to
40 s with heating up to 150 °C.
10
(a)
(b)
10 m
20 m
(c)
10 m
(d)
5 m
(2) (1)
Supplementary Figure 10. HR-TEM images (a) PbI2 located 200 nm deep from HaP film surface for
control-HaP, (b) α-HaP crystal orientation (blue: out-of-plane, red: in-plane), and (c and d) magnified images for the remnant PbI2.
image of area for δ-HaP located between PbI2 and α-HaP phase, (c) magnified image of area for the observation of interface between TiO2 and HaP in w/PbI2 sample.
12
Control HaP precursor
PbI2 excessed HaP precursor
Supplementary Figure 12. Comparison of size and distribution of iodoplumbate complex measured
by dynamic light scattering spectroscopy in control and w/PbI2 precursor solution.
13
Supplementary References (1) Liu, J., Saw, Robert E., Kiang, Y.-H., Calculation of Effective Penetration Depth in X-Ray Diffraction for Pharmaceutical Solids, J. Pharm. Sci. 99, 3807–3814 (2010).
