Supplementary Information
High performance planar p-i-n perovskite solar cells with
crown-ether functionalized fullerene and LiF as double cathode
buffer layers
Xiaodong Liu,1 Ming Lei,2 Yi Zhou,1,a) Bo Song,1,a) and Yongfang Li1,3,a)
1. Laboratory of Advanced Optoelectronic Materials, College of Chemistry,
Chemical Engineering and Materials Science, Soochow University, Suzhou,
Jiangsu 215123, China.
2. Department of Chemistry, Zhejiang University, Hangzhou 310027, China.
3. Beijing National Laboratory for Molecular Sciences, Institute of Chemistry,
Chinese Academy of Sciences, Beijing 100190, China.
a)
Corresponding author E-mail: yizhou@suda.edu.cn, songbo@suda.edu.cn,
liyf@iccas.ac.cn
1
Experimental section
Fabrication of p-i-n planar pero-SCs: The details on the preparation of the
perovskite CH3NH3PbI3-XClX layer and the PCBM acceptor layer, as well as the
fabrication and characterization of the p-i-n pero-SCs can be found in our previous
publication (X. Liu, H. Yu, L. Yan, Q. Dong, Q. Wan, Y. Zhou, B. Song, and Y. Li,
ACS Appl. Mater. Interfaces 7, 6230 (2015)). After the preparation of the perovskite
layer and PCBM layer, the ethanol solution of PCBC with a concentration of ca. 0.2
mg/mL was spin-coated on the PCBM layer at different spin-coating speeds for 50 s.
Since the PCBC layer is very thin, it is difficult to measure the thickness of PCBC on
the PCBM layer directly. The average thicknesses of the PCBC spin-coated on Si
substrates at various speeds were estimated to be ~1.83, 1.36, 1.30 and 0.95 nm at
800, 1200, 2000 and 3000 rpm, respectively, from measurements by spectroscopic
ellipsometry. Finally, LiF (1 nm) and Al electrode were sequentially deposited by
thermal evaporation at a base pressure of 1×10-4 Pa. The deposition rate and film
thickness were monitored with a quartz crystal sensor. A shadow mask was closely
covered on the sample to define an active area of 4 mm2 during the Al deposition. All
the devices were fabricated in the same batch (the same solution and electrode
evaporated at the same time) to avoid batch-to-batch variation.
Characterization: The J-V characteristics were measured using a Keithley 2400
source meter unit under simulated Air Mass 1.5 Global (AM 1.5 G) solar illumination
with an intensity of 100 mW/cm2. The incident photon-to-current conversion
efficiency (IPCE) was measured by a solar cell spectral response measurement system
(Enli Technology Co., Ltd., QE-R3011). The alternating current impedance
spectroscopy (ACIS) measurements were performed on IM6e electrochemical
workstation (Zahner Zennium, Germany) in dark condition, with an applied bias of
2
0.96 V. An AC signal with root-mean-square amplitude of 10 mV over the frequency
range of 4 MHz to 0.3 Hz was adopted during the measurement. As evaluating the
stability, the pero-SCs were stored and measured in the glovebox.
Figures
-Z (cm2)
18
12
6
PCBC
0
0
6
12
18
Z (cm )
2
FIG. S1. The Nyquist plot (symbol) and fitted curve (solid line) for the pero-SC based
on CH3NH3PbI3-xClx with PCBC single CBL, measured in the dark and with applied
voltage near to the Voc (0.97 V). Insert is the equivalent circuit used for fitting the
impedance data.
TABLE S1. The parameters of the equivalent circuit for the planar p-i-n pero-SC with
PCBC single CBL.
CBL
Ros(Ω cm2)
RCT(Ω cm2)
CPE-T (µF cm-2)
CPE-P
PCBC
1.09
19.38
0.19
0.96
3
1.0
0.8
0.6
Jsc
Voc
FF
PCE
0.4
0.2
Device performance
1.0
Device performance
Device performance
1.0
0.8
0.6
0.4
0.2
(a)
0.0
15
30
45
60
0.6
0.4
0.2
(c)
(b)
0.0
0.0
0
0.8
0
15
Time (days)
30
45
0
60
15
Time (days)
30
45
60
75
Time (days)
FIG. S2. Stability of the photovoltaic characteristics normalized by their initial values,
for the devices with (a) PCBC (800 rpm)/LiF, (b) PCBC (1200 rpm)/LiF and (c)
PCBC (3000 rpm)/LiF double CBLs, as a function of the storage time in the
glovebox.
5
0 day
39 days
44 days
48 days
55 days
70 days
0
-5
-10
-15
-20
-0.2
(a)
0.0
0.2
0.4
0.6
0.8
Current density (mA/cm2)
Current density (mA/cm2)
5
1.0
0
-5
-10
-15
(b)
-20
-0.2
Voltage (V)
0 day
39 days
44 days
48 days
55 days
70 days
0.0
0.2
0.4
0.6
0.8
1.0
Voltage (V)
FIG. S3. Evolution of the J-V curves of the pero-SCs, as a function of storage time in
the glovebox, for the devices with (a) PCBC (2000 rpm)/LiF double and (b) LiF
single CBLs.
4
Current density (mA/cm2)
0
-5
-10
LiF
PCBC
PCBC/LiF
-15
-20
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
Voltage (V)
FIG. S4. J-V curves of the pero-SCs with LiF single, PCBC single and PCBC/LiF
double CBLs after 154 days of storage in the glovebox.
TABLE S2. Photovoltaic performance of the p-i-n pero-SCs with different CBLs after
154 days of storage in the glovebox.
CBL
Jsc(mA/cm2)
Voc (V)
FF (%)
PCE (%)
LiF
3.79
0.88
13.3
0.44
PCBC
19.28
0.96
25.7
4.78
PCBC/LiF
18.96
0.99
27.3
5.13
5