Electronic Supplementary Information - The … Supplementary Information 2-Methoxyethanol as a new...
Transcript of Electronic Supplementary Information - The … Supplementary Information 2-Methoxyethanol as a new...
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Electronic Supplementary Information
2-Methoxyethanol as a new solvent for processing methyl ammonium lead
halide perovskite solar cells
Koen H. Hendriks, Jacobus J. van Franeker, Bardo J. Bruijnaers, Juan A. Anta, Martijn M. Wienk,
and René A. J. Janssen*
Table S1. Physical characteristics of solvents used for perovskite deposition.
Solvent Boiling Point (°C) Vapour Pressure at 20 °C (Pa)
2-Methoxyethanol (2ME) 124 823
N,N-Dimethylformamide (DMF) 153 360
-Butyrolactone (GBL) 206 200
N,N-Dimethylacetamide (DMAc) 165 176
Dimethylsulfoxide (DMSO) 189 56
N-Methylpyrrolidone (NMP) 203 39
Table S2. Slow sweep J–V characteristics for 2ME triple anion cells annealed for various times.
Anneal Time Voc (V) FF Jsc (mA/cm2) Jsc,sr(mA/cm2) PCE (%)
5 min 0.989 0.793 17.05 16.99 13.32
10 min 0.983 0.791 18.37 18.22 14.18
15 min 0.935 0.788 17.82 18.13 13.35
Electronic Supplementary Material (ESI) for Journal of Materials Chemistry A.This journal is © The Royal Society of Chemistry 2017
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Figure S1. AFM height images of the SEM images of methyl ammonium lead triiodide perovskite
layers processed on glass/ITO/PEDOT:PSS. (a) 10 μm × 10 μm, height 500 nm, Rq = 148 nm. (b)
10 μm × 10 μm, height 200 nm, Rq = 62 nm. (c) 5 μm × 5 μm, height 100 nm, Rq = 24 nm. (d) 5
μm × 5 μm, height 50 nm, Rq = 10 nm.
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-0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2-20
-15
-10
-5
0
5
10
Dark Fast up Fast down Slowsweep
Cur
rent
Den
sity
(m
A/c
m2)
Voltage (V)
DMF Single Anion
-0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2-20
-15
-10
-5
0
5
10
Dark Fast up Fast down Slowsweep
Curr
ent D
ens
ity (
mA
/cm
2)
Voltage (V)
2ME Single Anion
-0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2-20
-15
-10
-5
0
5
10
Dark Fast up Fast down Slowsweep
Cur
rent
Den
sity
(m
A/c
m2 )
Voltage (V)
DMF Triple Anion
-0.2 0.0 0.2 0.4 0.6 0.8 1.0 1.2-20
-15
-10
-5
0
5
10
Dark Fast up Fast down Slowsweep
Cur
rent
Den
sity
(m
A/c
m2 )
Voltage (V)
2ME Triple Anion
Figure S2. Upwards and downwards fast measurements (0.25 V/s), and slow sweep J–V curves
of the best perovskite cells made from single and triple anion precursors.
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0.80 0.85 0.90 0.95 1.00 1.050
5
10
15
20
25
# C
ells
Open-circuit Voltage (V)
DMF TA 2ME TA
0.70 0.75 0.80 0.850
5
10
15
20
# C
ells
Fill Factor
DMF TA 2ME TA
15 16 17 18 19 200
5
10
15
# C
ells
Short-circuit Current Density (mA/cm2)
DMF TA 2ME TA
0 20 40 60 80 100 12013
14
15
16
2ME DMF
Time (s)
Pm
ax (m
W/c
m2 )
0.0
0.2
0.4
0.6
0.8
1.0
App
lied
bia
s (V
)
(b)
Figure S3. Histograms and normal curves of all fabricated devices using 2ME or DMF triple anion
precursor solutions, determined by a fast downward J–V sweep in the solar simulator, (a) Voc, (b)
FF, and (c) Jsc. (d) Maximum power point tracking curves for the best solar cells, showing the
applied bias (dotted line) and Pmax (thick line) measured by the solar simulator.
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Figure S4. SEM images of perovskite layers processed on glass/PEDOT:PSS (left), glass/PSSH
(middle), and glass (right) for photoluminescence lifetime measurements. From top to bottom:
2ME single anion, 2ME triple anion and DMF triple anion.
2ME SA PEDOT:PSS PSSH Glass
2ME TA PEDOT:PSS PSSH Glass
DMF TA PEDOT:PSS PSSH Glass
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700 720 740 760 780 800 820 840102
103
104
Cou
nts
Wavelength (nm)
2ME SA DMF TA 2ME TA
(a)
0 200 400 600 800 1000
101
102
103
Cou
nts
Time (ns)
2ME SA DMF TA 2ME TA
3.9 ns
225 ns
238 ns
(b)
Figure S5. (a) Photoluminescence emission spectra and (b) photoluminescence decay traces of
perovskite layers on glass processed from 2ME or DMF. The solid lines are the stretched
exponential fits. The lifetimes depicted in the graph are the average lifetimes for the respective
curves. For the single-anion precursor a stretched exponential does not fit that data correctly and
an amplitude average lifetime was determined from a tri-exponential fit.
Table S3. Time resolved fluorescence data fit to a stretched exponential decaya
Precursor Solvent Substrate τc (ns) β < τ > (ns) τave (ns) b
Triple-anion DMF PSSH 618 0.66 828 855
Glass 68 0.40 225 195
2ME PSSH 125 0.57 202 219
Glass 49 0.35 238 183
Single-anion 2ME PSSH 2 0.64 3 3.8
Glass 2 0.93 2 3.9
a c( / )( ) (0) tI t I e where τc is the lifetime, β the distribution coefficient, and
1c( ) ( ) the average lifetime. b Amplitude average lifetime determined from a bi-
exponential (for triple-anion) and tri-exponential (for sing-anion) fits.
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0 250 500 750 1000 1250 1500 1750
0
-250
-500
-750
-1000
0.858 V 0.881 V 0.908 V 0.926 V 0.942 V 0.961 V
Z''
Z'
DMF Triple Anion
0 250 500 750 1000 1250 1500 1750
0
-250
-500
-750
-1000
0.891 V 0.915 V 0.943 V 0.961 V 0.977 V 0.999 V 1.016 V
Z''
Z'
2ME Triple Anion
Figure S6. Nyquist plots of impedance data measured at open-circuit conditions at various light
intensities of perovskite solar cells processed from triple anion precursors of (a) DMF and (b) 2ME.
The solid dots are the measured data points, the lines are fits of the medium-frequency arc to an -
Rs(RrecC)- equivalent circuit.
Figure S7. Low magnification cross-section SEM images of perovskite solar cells processed from
2ME and DMF triple anion precursors.
2ME Triple Anion DMF Triple Anion
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-0.5 0.0 0.5 1.0 1.51E-6
1E-5
1E-4
1E-3
0.01
0.1
1
10
100
Cur
rent
Den
sity
(m
A/c
m2 )
Bias (V)
DMF Triple Anion 2ME Tiple Anion
Figure S8. Fast downward J-V sweeps in the dark of the DMF and 2ME triple anion processed
cells shown in Table 1 and Figure 2 (thin lines) showing that the 2ME cells have a lower dark
current. The thick lines with symbols are the average dark curves. The fact that not all curves have
a minimum current density at 0 V is likely due to the fast measurement protocol, inducing a
displacement current or it is related to the little hysteresis that is present.