Highly Efficient Perovskite Solar Cells with Substantial Reduction of Lead Content Chong Liu†, Jiandong Fan†‡*, Hongliang Li†, Cuiling Zhang†, Yaohua Mai†‡* †
Institute of Photovoltaics, College of Physics Science and Technology, Hebei University, Baoding, 071002, China ‡
Institute of New Energy Technology ,College of Information and Technology, Jinan University, Guangzhou, 510632, China E-mail: (J. F.)
[email protected]; E-mail: (Y. M.)
[email protected].
1
(x =1 )i
@ n
Intensity (a.u.)
(x =1 )i
n
(x =0 .5 )i
DM
n
@
@#
@ SnI2/PbI2
DM F
#
# FTO & PbI2(DMSO)x SnI2(DMSO)x
#
*
*
SO
DM SO
،¤ DM F
&
(x=
0) in
DM SO
5
*
،¤D MF
10
*
&
&
&
15
*
*
20
25
30
35
40
2Theta (deg) Supplementary Figure 1. XRD patterns of PbI2/(SnI2)·(DMSO)x complexes with different Sn concentrations after post annealing treatment at 90 ºC for 10 min.
C=O
C=O
B
C-O
SnI2 in DMSO/DMF_60C/10min
Intensity (a.u.)
B
C-O C-S
PbI2 in DMSO/DMF_W/O anneal
C-S
SnI2 in DMSO/DMF_W/O anneal
C-S
C-O C-S
PbI2 in DMSO/DMF_60C/10min
B
Intensity (a.u.)
C-O
PbI2 in DMSO/DMF_140C/20min
SnI2 in DMSO/DMF_140C/20min
500
1000 1500 2000 2500 3000 3500 4000
500
Wavenumber (cm-1)
1000 1500 2000 2500 3000 3500 4000
Wavenumber (cm-1)
Supplementary Figure 2. FTIR spectra of the perovskite layer deposited from DMSO/DMF solution before and after annealing showing the characteristic C−S and C−O stretching vibrations from the Sn2+- and Pb2+- coordinated DMSO solvent at 960 and 1012 cm−1, and C=O stretching vibrations from the Sn2+- and/or Pb2+- coordinated DMF solvent at 1389 and 1688 cm−1. (a) SnI2·(DMSO)x intermediates; (b) PbI2·(DMSO)x intermediates.
2
Supplementary Figure 3. SEM images of PbI2/(SnI2)·(DMSO)x complexes with different Sn concentrations.
3
Supplementary
Figure 4. SEM images of CH3NH3Pb(1−x)SnxI3 (0≤x≤1) thin films with
different Sn concentrations.
O
I
X=0
3d5/2
Sn
3d3/2
Pb
4f7/2
4f5/2
Intensity (a.u.)
X=0.25
X=0.5
1s
530
3d5/2
X=1 535
540
Binding Energy (eV)
545
620
625
630
635
640
485
490
3d3/2
495
Binding Energy (eV)
Binding Energy (eV)
500
140
145
150
Binding Energy (eV)
Supplementary Figure 5. XPS spectra of Pb, I, Sn and O in CH3NH3Pb(1−x)SnxI3 (0≤x≤1) thin films with different Sn concentrations. 4
PCBM/BCP/Ag MAPb0.75Sn0.25I3 PEDOT:PSS FTO
1 μm
Supplementary Figure 6. The cross-sectional SEM image of CH3NH3Pb0.75Sn0.25I3 solar cell with inverted structure.
20
16
18
14
12
12 PCE
10 8
10 8
PCE (%)
Current Density (mA/cm2)
Current Density
14
18
nsity
10
10
8
8
4
2
2
0
0
0
-2
-2
-2
50 100 150 200 250 300 350 400 450 Time (s)
Current De
12
6
14 12
14
4
0
(b)
16
6
-50
16
PCE
6
PCE (%)
(a)
16
Current Density (mA/cm2)
18
6 4
4
2
2 0
0
100
200
300
400
500
Time (s)
Supplementary Figure 7. Photocurrent density and power conversion efficiency as a function of time for the same cell held close to 0.79 V and 0.60 V forward bias, respectively. (a) CH3NH3PbI3; (b)CH3NH3Pb0.75Sn0.25I3
5