Supporting Information
Journal: Scientific Reports
Full Printable Processed Mesoscopic CH3NH3PbI3/TiO2 Heterojunction Solar
Cells with Carbon Counter Electrode
Zhiliang Ku, Yaoguang Rong, Mi Xu, Tongfa Liu, Hongwei Han*
Michael Grätzel Center for Mesoscopic Solar Cells, Wuhan National Laboratory for
Optoelectronics, School of Optical and Electronic Information, Huazhong University of
Science and Technology, Wuhan, Hubei 430074, PR China
* Correspondence and requests for materials should be addressed to H.W. H.
(hongwei.han@mail.hust.edu.cn)
Figure S1 The J-V characteristic of the monolithic CH3NH3PbI3 perovskite/TiO2 heterojunction
solar cells based on different thickness of carbon CEs.
Figure S1 shows that the device with 5µm carbon CE possessing the highest Jsc. As the
increasing of CE thickness, the Jsc shows a decrease trend. We attribute the higher Jsc to the more
sufficient pore-filling of CH3NH3PbI3 perovskite in TiO2 film, because the thinner carbon CE on
top of the device permit more content of CH3NH3PbI3 filling into TiO2 film. On the other hand,
the conductivity of 5µm carbon CE is so poor that the FF of the device still remains low value.
When the carbon CE thickness increase to 10µm, the PCE of the device reaches the highest value,
due to the promising FF and Jsc values. However, the 20µm CE seemed to be a major obstacle for
the penetration of CH3NH3PbI3 perovskite, rendering a much lower FF of the device. Hence, we
choose 10µm as an appropriate CE thickness in the fabrication of CH3NH3PbI3 perovskite/TiO2
heterojunction solar cells.
Figure S2 XRD pattern of the CH3NH3PbI3 perovskite on glass.
Table S1. Conductivity of carbon/graphite films with different thickness
thickness
5µm
10µm
20µm
Carbon/spheroidal graphite
19.87Ω/cm2
8.02Ω/cm2
4.22Ω/cm2
Carbon/flaky graphite
33.65Ω/cm2
10.49Ω/cm2
5.84Ω/cm2
Four-point probe measurement has been used to investigate the conductivity of
carbon/graphite films with different thickness. The carbon/spheroidal graphite film present higher
conductibity than the cabon/flaky graphite film when the thickness is lower than 20µm.
Figure S3 J-V curves of 20 separate devices based on carbon/spheroidal graphite and carbon/flaky
graphite counter electrodes.
Table S2. The photovoltaic parameters of the 20 separate devices.
Sample
Jsc (mA/cm2)
Voc (mV)
FF
PCE
Spheroidal graphite 1
2
3
4
5
6
7
8
9
10
Flaky graphite
1
2
3
4
5
6
7
8
9
10
12.1
12.4
12.4
12.1
12.3
11.8
12.3
12.2
12.4
12.7
10.1
10.6
10.1
9.88
9.97
10.1
10.2
10.1
10.1
9.82
870
875
887
885
880
882
885
885
878
868
805
825
823
813
817
797
827
832
831
826
0.60
0.58
0.60
0.60
0.59
0.63
0.60
0.61
0.61
0.58
0.45
0.46
0.45
0.45
0.46
0.43
0.46
0.47
0.47
0.44
6.32%
6.09%
6.60%
6.42%
6.39%
6.56%
6.53%
6.58%
6.64%
6.39%
3.66%
4.08%
3.71%
3.69%
3.99%
3.46%
3.88%
3.95%
3.94%
3.57%
Figure S4 The real monolithic devices with (right) and without (left) carbon CEs.
As shown in Figure S4, the carbon black/graphite CEs can be printed on numbers of devices
at one time, implying a good reproducibility and a great positive prospect for commercial
production.