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Plasmonic Enhancement of Dye Sensitized Solar Cells

in the Red-to-NIR Region using Triangular Core-Shell

Ag@SiO2 Nanoparticles

Mahesh K. Gangishetty,† Kee Eun Lee,

† Robert W. J. Scott, and Timothy L. Kelly*

Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, SK, S7N

5C9, Canada

† These authors contributed equally to this work.

* Address correspondence to: tim.kelly@usask.ca

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Figure S1. TEM images of the as-prepared silver nanoprisms.

Figure S2. Size distributions of the as-prepared silver nanoprisms: (a) edge length, and (b)

thickness.

10 15 20 25 30 35 40 45 50 55 600

10

20

30

40

(a)

Counts

Nanoprism Edge Length (nm)

0 1 2 3 4 50

5

10

15

20

25

30(b)

Counts

Nanoprism Thickness (nm)

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Figure S3. UV/Vis/NIR spectra of the as-prepared silver nanoprisms (black line) and the

nanoprisms after functionalization with 16-mercaptohexadecanoic acid (red line).

Figure S4. Schematic depiction of the device architecture, showing the Ag@SiO2 nanoparticles

embedded in the TiO2 photoanode.

400 500 600 700 800 900 10000.0

0.2

0.4

0.6

0.8

1.0

Optical Density

Wavelength (nm)

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Table S1. Analysis of variance (ANOVA) analysis of power conversion efficiency as a function of

Ag@SiO2 loading, carried out at the 95% confidence level. The calculated F-value (13.3) is larger

than the critical F-value (2.3) required for 95% confidence, and the P-value is less than 0.05.

Therefore, the results show a statistically significant variation in PCE with Ag@SiO2 loading.

Anova: Single Factor

SUMMARY

Ag@SiO2 Loading Count Sum Average Variance

0.00% 15 83.1881 5.545873 0.367689

0.01% 4 25.3545 6.338625 0.25448

0.05% 13 95.8342 7.371862 0.465648

0.10% 4 28.4597 7.114925 0.170996

0.33% 6 40.1648 6.694133 0.251301

0.50% 4 27.2061 6.801525 0.087758

1.00% 4 27.0449 6.761225 0.127536

ANOVA

Source of Variation SS df MS F P-value F crit

Between Groups 25.91521 6 4.319202 13.34788 1.78E-08 2.318498

Within Groups 13.91425 43 0.323587

Total 39.82946 49

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Table S2. Pairwise t-tests (assuming unequal variances, 95% confidence) comparing the power

conversion efficiencies of devices made with various Ag@SiO2 loadings with pure TiO2 controls. In

all cases, the absolute value of the t-statistic is larger than the critical t-value required for 95%

confidence in a two-tailed test, and the P-value is less than 0.05. Therefore, each sample shows a

statistically significant increase in PCE relative to the TiO2 controls.

Ag@SiO2 Loading 0.00% 0.01% 0.00% 0.05% 0.00% 0.10%

Mean 5.546 6.339 5.546 7.372 5.546 7.115

Variance 0.368 0.254 0.368 0.466 0.368 0.171

Observations 15 4 15 13 15 4

Hypothesized Mean Difference 0 0 0

df 6 24 7

t Stat -2.670 -7.434 -6.050

P(T<=t) one-tail 0.019 0.000 0.000

t Critical one-tail 1.943 1.711 1.895

P(T<=t) two-tail 0.0370

1.13E-

07 0.0005

t Critical two-tail 2.447 2.064 2.365

Ag@SiO2 Loading 0.00% 0.33% 0.00% 0.50% 0.00% 1.00%

Mean 5.546 6.694 5.546 6.802 5.546 6.761

Variance 0.368 0.251 0.368 0.088 0.368 0.128

Observations 15 6 15 4 15 4

Hypothesized Mean Difference 0 0 0

df 11 11 8

t Stat -4.456 -5.826 -5.118

P(T<=t) one-tail 0.000 0.000 0.000

t Critical one-tail 1.796 1.796 1.860

P(T<=t) two-tail 0.0010 0.0001 0.0009

t Critical two-tail 2.201 2.201 2.306

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Figure S5. (a) Incident photon-to-current efficiency spectra of DSSCs made using 0.0% (black line)

and 0.05% (red line) Ag@SiO2 loadings. The difference spectrum is also shown (blue line). (b) The

relative IPCE enhancement ((IPCEAg@SiO2 − IPCEcontrol) / IPCEcontrol) for the device with a 0.05%

Ag@SiO2 loading (blue line) and the original IPCE spectrum (black line).

Figure S6. TEM image of the Ag@SiO2 nanoparticles with the thickest SiO2 shells after sintering.

300 400 500 600 700 800 9000

10

20

30

40

50

60

70

80 0.0% Ag

0.05% Ag

Difference

IPCE (%)

Wavelength (nm)

(a)

300 400 500 600 7000

10

20

30

40

50

60

70

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

IPCE (%)

Wavelength (nm)

(b)∆∆ ∆∆ IPCE / IP

CE

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Figure S7. Average power conversion efficiency for DSSCs prepared using 0.05% (w/w) of

Ag@SiO2 nanoprisms with different shell thicknesses, as well as for the control devices without any

Ag@SiO2. The thickness of the photoanode in all devices was 3 – 4 µm. The error bars show plus

or minus one standard deviation from the mean.

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5

6

7

33 nm SiO2

7 nm SiO2

Power Conversion Efficiency (%)

TiO2 Control

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Table S3. Device performance characteristics for DSSCs prepared using 0.05% (w/w) of Ag@SiO2

nanoprisms with different shell thicknesses, as well as for the control devices without any

Ag@SiO2. The thickness of the photoanode in all devices was 3 – 4 µm.

Device Type Average

VOC (V)

Average JSC

(mA/cm2)

Average FF

(%)

Average

PCE (%)

TiO2 Control 0.63 ± 0.02 9.3 ± 0.8 72.9 ± 0.2 4.3 ± 0.5

7 nm Ag@SiO2 0.68 ± 0.01 9.1 ± 0.6 73.3 ± 0.8 4.6 ± 0.3

33 nm Ag@SiO2 0.65 ± 0.01 12.9 ± 0.9 71.7 ± 0.8 6.1 ± 0.5