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Electronic Supporting Information
Investigation into fluorescence quenching behaviors and applications of carbon dots
Yubin Song+, Shoujun Zhu,+ Siyuan Xiang, Xiaohuan Zhao, Junhu Zhang, Hao Zhang, Yu Fu and Bai Yang*
Figure S1 The normalized PL spectra of CDs in phosphate buffer solution with different pH values. The concentration of CDs was 0.01 mg/mL; The PL was excited at 360 nm.
350 400 450 500 550 600
0.0
0.2
0.4
0.6
0.8
1.0
PL In
tens
ity /
a.u.
Wavelength / nm
5.7 6 6.5 7 7.5 8
pH
Electronic Supplementary Material (ESI) for Nanoscale.This journal is © The Royal Society of Chemistry 2014
Figure S2 The influence of pH in CDs aqueous solution. The concentrations of CDs were at identical value; The PL was excited at 360 nm.
0 1 2 3 4 5 6 7 8 9 10111213140
100
200
300
400
500
600
PL In
tens
ity
pH
Figure S3 The lifetime of CDs by adding different amount of Fe3+.
0 20 40 60 80 100
0
2000
4000
6000
8000
10000 In
tens
ity /
a.u.
Decay time / ns
0 20 40 60 80 100 250 1750 2500 IRF
Fe3+ /
Fe3+ / M τ1 / ns p1 / % τ2 / ns p2 / % 2average
lifetime / ns0 1.50 1.83 14.78 98.17 1.324 14.54
20 2.17 2.52 14.50 97.48 1.348 14.19 40 2.21 3.21 14.22 96.79 1.351 13.83 60 2.35 3.65 13.94 96.35 1.175 13.52 80 2.29 3.77 13.58 96.23 1.271 13.15
100 2.27 3.96 13.25 96.04 1.323 12.82 250 2.47 6.32 12.65 93.68 1.283 12.01
1750 2.48 7.37 10.86 92.63 1.157 10.24 2500 2.63 8.37 10.41 91.63 1.116 9.76
Figure S4 a) The PL spectra of CDs with different concentration of I-. b) Relative PL intensity (F0/F-1) of CDs solution as a function of the addition amount of I- . The concentration of CDs was 0.01 mg/mL; The PL was excited at 360 nm.
400 450 500 550 6000
50
100
150
200
250
300
PL In
tens
ity
Wavelength / nm
0 0.01M 0.1M 1M
concentration of I-
0.00 0.02 0.04 0.06 0.08 0.10
0.0
0.5
1.0
1.5
2.0
2.5
3.0
F 0/F-1
I- / M
y=-0.00764+26.25011xr=0.99877
a)
b)
Figure S5 Ferric ion detection curve with different concentration of CDs.
0 50 100 150 200 2500.00.51.01.52.02.53.03.54.0
F 0/F-1
Fe3+M
0.05 0.01 0.001 0.0001
CDs / mg/mL
Figure S6 The PL peak of CDs as a function of the concentration of Fe3+ (CDs=0.01 mg/mL).
0 50 100 150 200 250448450452454456458460462464
PL P
eak
/ nm
Fe3+ /
y=450.32+0.0569xr=0.99194
Figure S7 The PL spectra of CDs with different concentration of Fe3+. The concentration of CDs was 0.01 mg/mL; The PL was excited at 360 nm.
350 400 450 500 550 6000
100
200
300
400
500PL
Inte
nsity
Wavelength / nm
0 50 100 250
In HAC-NaACbuffer solution
Fe3+ /
Figure S8 Relative PL intensity (F0/F-1) of CDs as a function of hemin concentration. The concentration of CDs was 0.01 mg/mL; The PL was excited at 360 nm.
0 50 100 150 200012345678
F 0/F-1
Hemin /
Figure S9 The lifetime of CDs exposure to high power UV light.
0 20 40 60 80 100
0
2000
4000
6000
8000
10000In
tens
ity /
a.u.
Decay time / ns
0 10 30 60 120 180 400 600 900 1200 IRF
UV Time / s
UV time / s τ1 / ns p1 / % τ2 / ns p2 / % 2average
lifetime / ns0 1.72 2.00 14.85 98.00 1.205 14.59
10 1.60 1.92 14.83 98.08 1.458 14.58 30 3.19 5.68 14.56 94.32 1.316 13.91 60 4.25 16.41 14.28 83.59 1.431 12.63
120 4.47 33.42 13.22 66.58 1.623 10.30 180 4.52 45.62 12.24 54.38 1.848 8.72 400 3.40 37.38 8.99 62.62 2.067 6.90 600 3.01 36.49 8.82 63.51 2.112 6.70 900 2.58 36.60 8.90 63.40 2.124 6.59
1200 2.34 37.82 8.87 62.18 2.288 6.40
Figure S10 The PL intensity of different adding sequences in H2O2/Fe2+/CDs system. The concentration of CDs, Fe2+ and H2O2 is 0.01 mg/mL, 250 μM and 5*10-5%, respectively. 1, the adding sequence was CDs, Fe2+ and H2O2, respectively. 2, the adding sequence was CDs, H2O2 and Fe2+, respectively. 3, the adding sequence was Fe2+, CDs and H2O2, respectively. 4, the adding sequence was Fe2+, H2O2, and CDs, respectively. 5, the adding sequence was H2O2, Fe2+ and CDs, respectively. 6, the adding sequence was H2O2 and CDs, Fe2+, respectively. Note: Two reagents were mixed and stayed for 5 min before the third reagent was added.
237.6 246.4 236.6
489.0 482.3
241.1
0.0
100.0
200.0
300.0
400.0
500.0
600.0
1 2 3 4 5 6
PL
Inte
nsity
Figure S11 The influence of Fe2+ concentration in CDs/H2O2 system (CDs 0.01 mg/mL, H2O2 5*10-5%). The concentration of Fe2+ (higher than 40 M) hardly affected the detection system, since Fe2+ mainly played catalysis role.
0 10 20 30 400
100200300400500600700
PL In
tens
ity
FeCl2 /
Figure S12 The lifetime of CDs/Fe2+ with adding different amount of H2O2.
0 20 40 60 80 100
0
2000
4000
6000
8000
10000In
tens
ity /
a.u.
Decay time / ns
0 2 4 6 8 10 IRF
H2O2 / *10-5%
H2O2 / % τ1 / ns p1 / % τ2 / ns p2 / % 2average
lifetime / ns0 1.80 2.03 14.85 97.97 1.258 14.59
2*10-5 3.02 7.27 14.58 92.73 1.261 13.74
4*10-5 3.35 13.11 14.34 86.89 1.397 12.90
6*10-5 3.61 22.32 13.92 77.68 1.570 11.62
8*10-5 3.65 31.03 12.86 68.97 1.754 10.00
10*10-5 3.66 38.83 11.87 61.17 1.717 8.68
Figure S13 a) Relative PL intensity (F0/F-1) of CDs/Fe2+ as a function of H2O2 solution mass fraction with low concentration. The concentration of CDs was 0.001 mg/mL and the concentration of ferrous ion was 10 M. b) H2O2/Fe2+/CDs system in PBS buffer solution. c) H2O2/Fe2+/CDs system in HAC-NaAC buffer solution. d) The H2O2/Fe2+/CDs quenching system can be achieved by adding H2O2 step by step (Inset is linear relation). The concentration of CDs was 0.01 mg/mL in b-d.
Figure S14 AFM images of CDs in different concentrations. a) 0.003 mg/mL CDs, b) 0.1 mg/mL CDs c) 1 mg/mL CDs
m
m
m
a)
b)
c)
Figure S15 a) Excitation-dependent PL of CDs. b) Excitation-dependent PL of CDs, which were synthesized in acid condition.
350 400 450 500 550 600
PL In
tens
ity /
a.u.
Wavelength / nm
300 320 340 360 380 400 420 440
EX / nm
350 400 450 500 550 600 650
PL In
tens
ity /
a.u. 300
320 340 360 380 400 420 440 460 480
Wavelength / nm
EX / nm
a)
b)