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Meng Hu, Yu Yang, Xiaoyu Gu, Yang Hu, Jian Huang, and Chaoyang Wang. 1. Table S1. Fluorescence quantum yield and product yield of C-dots from different.
Electronic Supplementary Material (ESI) for RSC Advances. This journal is © The Royal Society of Chemistry 2014

Electronic Supplementary Information

One-pot synthesis of photoluminescent carbon dots by carbonization of cyclodextrin and their application in Ag+ detection Meng Hu, Yu Yang, Xiaoyu Gu, Yang Hu, Jian Huang, and Chaoyang Wang1

Table S1. Fluorescence quantum yield and product yield of C-dots from different carbohydrates. Samples -Cyclodextrin Fructose Glucose Citrate

Quantum yield 13.5% 11.5% 7.5% -

Yield 34% 8% 13% -

Table S2. The yield of C-dots from -cyclodextrin at different temperatures Temperature (oC) Yield (%) .

50 0

60 16

70 34

80 23

90 11

50 oC

60 oC

70 oC

80 oC

90 oC

Figure. S1. Photographs of solutions with -cyclodextrin (2 g), hydrochloric acid (15 mL, 36-38 wt.%) and deionized water (15 mL) at different temperatures for 4 h.

Figure. S2. Carbon spheres formed by further dehydration and aggregation of C-dots.

a

40

Percentage (%)

c 30

20

10

0 1.5

2.0

2.5

3.0

3.5

4.0

Size (nm)

b

40

Percentage (%)

d 30

20

10

0 1.5

2.0

2.5

3.0

3.5

Size (nm)

Figure. S3. (a,b) TEM images and (c,d) size histograms (counting 100 particles at least) of C-dots synthesized from  and -cyclodextrins, respectively. Scale bars in a,b: 20 nm..

4.0

Intensiy (a.u.)

a

b

c

20

40

60

80

2  (Degree) Figure. S4. (a-c) XRD patterns of C-dots synthesized from , and -cyclodextrins, respectively.

Transmittance (%)

a

b

2926 3416

C-H

c

1643 1418

C=O 

850 765

C-O1028

O-H

C-H

C-O

4000 3500 3000 2500 2000 1500 1000

500

Wavelength (cm-1) Figure. S5. (a-c) FT-IR spectra of C-dots synthesized from ,  and -cyclodextrins, respectively.

500

Counts

400

a b c

300 200 100 0

5

10

15

20

25

30

Time (ns) Figure. S6. (a-c) Fluorescence decay profiles of C-dots synthesized from , and -cyclodextrins, respectively.

a

30 min under sunlight

c

b

d 12 h in dark

Figure. S7. (a, b) Photographs of C-dots (200 mg/L) and AgNO3 (200 M) mixture before and after reaction under sunlight for 30 min. (c,d) Photographs of C-dots (200 mg/L) and AgNO3 (200 M) mixture before and after reaction in dark for 12h.

PL Intensity (a.u.)

200

[Ag+] (M) 0 1 10 25 50

160 120 80 40 0

500

550

600

650

Wavelength (nm) Figure. S8. Representative FL emission spectra of aqueous solutions of C-dots (100 mg/L) and AgNO3 with different concentrations (0-25 M) after 30 min under sunlight.

e h sunlight

PL intensity strengthen Low concentration of Ag+

Ag e h PL intensity weaken

C-dot

Ag0

High concentration of Ag+

Figure. S9. Schematic representation of reduction of Ag+ to Ag0 by C-dots under sunlight.

50

a

b

40

Volume (%)

Volume (%)

40

50

30 20 10

30 20 10

0 -1 10

0

10

1

10

2

10

0 -1 10

3

10

0

10

Size (nm) 50

c

20 10

3

2

10

30 20 10

0 -1 10

0

10

1

10

2

10

0 -1 10

3

10

0

10

1

10

3

10

Size (nm)

Size (nm) 50

100

e

80

Size (nm)

Volume (%)

10

d

40

30

40

2

10

50

Volume (%)

Volume (%)

40

1

10

Size (nm)

30 20

f

60 40 20

10 0

0 -1 10

0

10

1

10

Size (nm)

2

10

3

10

0

100

200

300

400

500

[Ag+] (mM)

Figure. S10. Size distribution of C-dots (100 mg/L) with different concentrations of AgNO3 after 30 min under sunlight: (a) 1, (b) 10, (c) 25, (d) 50, (e) 500 M. (f) The relationship between the average particle size and AgNO3 concentration.