Supplementary Materials for · Figure S2. Structural characterizations of the five selected...

advances.sciencemag.org/cgi/content/full/6/40/eabb6772/DC1

Supplementary Materials for

Full-color fluorescent carbon quantum dots

Liang Wang*, Weitao Li, Luqiao Yin, Yijian Liu, Huazhang Guo, Jiawei Lai, Yu Han, Gao Li, Ming Li, Jianhua Zhang,

Robert Vajtai, Pulickel M. Ajayan, Minghong Wu*

*Corresponding author. Email: [email protected] (L.W.); [email protected] (M.W.)

Published 2 October 2020, Sci. Adv. 6, eabb6772 (2020)

DOI: 10.1126/sciadv.abb6772

This PDF file includes:

Supplementary Text Figs. S1 to S7 Tables S1 to S3

Supplementary Text

Details for cytotoxicity test and cell imaging

Cytotoxicity test

First, the o-CQDs was converted to phosphate-buffered saline (PBS) through rotary evaporation.

Hela cells were cultured in DMEM medium with 1% penicillintreptomycin and 10% fetal bovine

serum (Hyclone, USA) at 37 oC in a Thermo cell incubator with 5% CO2. MTT method was taken

to estimate the cytotoxicity of o-CQDs. In short, cells were seeded in 96 wells plates, and about

5000 cells in each well. Different concentrations of o-CQDs (20, 40, 60, 80, and 100 mg·L-1) were

added to each group. After 24 and 48 hours in culture, MTT (5 mg·mL-1) was added and incubated

at 37 oC for four hours. Then, a microplate reader (ELX 00 UV, BIO-TEK, USA) was used to get

the result.

Cell imaging of o-CQDs

The method of cultivating o-CQDs and cells is the same as above. Approximately 2×105 cells were

seeded in a glass-bottom dish (35 mm dish with 14 mm glass-bottom well) with the 2 mL culture

medium. After 24 hours in culture, o-CQDs (20 mg·L-1) was added into the dish. Then after an

incubation of 30 min, the cells were examined under a confocal microscope (Leica TCS SP5, GER)

using lasers of 405, 488 and 543 nm.

Figure S1. Reaction acid reagent and solvent regulation of CQDs. (A) CQDs photographs under

UV light irradiation using different acid reagents with oPD. From left to right, these samples were

produced by solvothermal treatment of oPD with H2SO4, HNO3, uric acid, H3PO4, HCl, citric acid,

oxalic acid, edetic acid, and p-aminobenzoic acid, respectively. (B) CQDs photographs under UV

light irradiation using pure oPD and pure selected acid reagents. From left to right, these samples

were produced by solvothermal treatment of pure 4-ABSA, pure FA, pure BA, pure AA, pure TPA,

pure TA, and pure oPD, respectively. (C, D) Absorption and Normalized PL spectra of CQDs

produced in water solution. (E, F) Absorption and Normalized PL spectra of CQDs produced in

toluene solvent. (G, H) Absorption and Normalized PL spectra of CQDs produced in DMF solvent.

400 500 600Wavelength (nm)

700 800

PL Inte

nsity

(a. u.)

DTATPAAAFABA


700 800

Inte

nsity

(a. u

.)

C

4-ABSA

TATPAAAFABA4-ABSA

300 300


700 800

PL Inte

nsity

(a. u.)

FTATPAAAFABA


700 800

Inte

nsity

(a. u

.)

E

4-ABSA

TATPAAAFABA4-ABSA

300


700 800

PL Inte

nsity

(a. u.)

HTATPAAAFABA


700 800

Inte

nsity

(a. u

.)

G

4-ABSA

TATPAAAFABA4-ABSA

300 300

A

B

Figure S2. Structural characterizations of the five selected CQDs. (A) FT-IR spectra of the five

selected CQDs. (B) 13C NMR spectra of the five selected CQDs. (C) 1H NMR spectra of the five

selected CQDs. (D) XPS survey spectra of the five selected CQDs. (E) High-resolution C1s spectra

of the five selected CQDs. (F) High-resolution N1s spectra of the five selected CQDs. (G) High-

resolution O1s spectra of the five selected CQDs. (H) High-resolution S2p spectrum of the b-CQDs.

(I) High-resolution B1s spectrum of the yg-CQDs. (J) XRD spectra of the five selected CQDs. (K)

Raman spectra of the five selected CQDs.

r-CQDs

o-CQDs

yg-CQDs

c-CQDs

b-CQDs

4000 3000 2000 1000Wavenumber (cm-1)

Inte

nsity

(a. u

.)

C=CC-O

B-CB-O

SO3

O-H/N-H

C=O

10 20 30 40 50 60 70 80

r-CQDs

o-CQDs

yg-CQDs

c-CQDs

b-CQDs

Inte

nsity

(a. u

.)

2 Theta (degree)

B

500 1000 1500 2000Raman shift (cm-1)

Inte

nsity

(a. u

.)

2500

DG r-CQDs

o-CQDsyg-CQDsc-CQDsb-CQDs

Ar-CQDs

o-CQDs

yg-CQDs

c-CQDs

b-CQDs

200 150 100 0ppm

Inte

nsity

(a. u

.)

50

Sp2 C

DMSO

Cr-CQDs

o-CQDs

yg-CQDs

c-CQDs

b-CQDs

10 8 6 0ppm

Inte

nsity

(a. u

.)

4 2

Aromatic ring

hy drogen+Ph-NH2

H2O

DMSO

J

0 200 400 800Binding energy (eV)

Inte

nsity

(a. u

.)

ED


Inte

nsity

(a. u

.)

295

F


Inte

nsity

(a. u

.)

405600


Inte

nsity

(a. u

.)

HG


Inte

nsity

(a. u

.)

170

I


Inte

nsity

(a. u

.)

195540

B1sS2pO1s

N1sC1s

B1s

S2p

C1s N1s O1s

C=O C-O

NH2C=C/C-C C-N/C-O

C=O

C-B

-SO3/2p3/2

-SO3/2p1/2

B-OB-C

KJ

r-CQDs

o-CQDs

yg-CQDs

c-CQDs

b-CQDs

b-CQDs yg-CQDs

r-CQDs

o-CQDs

yg-CQDs

c-CQDs

b-CQDs

r-CQDs

o-CQDs

yg-CQDs

c-CQDs

b-CQDs

r-CQDs

o-CQDs

yg-CQDs

c-CQDs

b-CQDs

Figure S3. Optimized preparation conditions of the five selected CQDs using PL QYs as a

reference. (A) 4-ABSA concentration optimization of the b-CQDs. (B) Temperature optimization

of the b-CQDs. (C) FA concentration optimization of the c-CQDs. (D) Temperature optimization

of the c-CQDs. (E) BA concentration optimization of the yg-CQDs. (F) Temperature optimization

of the yg-CQDs. (G) AA concentration optimization of the o-CQDs. (H) Temperature optimization

of the o-CQDs. (I) TPA concentration optimization of the r-CQDs. (J) Temperature optimization

of the r-CQDs. (K) Photographs of Rhodamine 6G and yg-CQDs under daylight (left) and UV light

(right), respectively.

Rhodamine 6G yg-CQDs

K

PL Q

Ys (

%)

120 150 180 200T (oC)

B 50

40

30

20

10

0

50

40

30

20

10

0

4-ABSA (mg)

PL Q

Ys (

%)

A

10 20 50 100 150 200 300

PL Q

Ys (

%)

120 150 180 200T (oC)

J 60

50

40

30

20

10

0

60

50

40

30

20

10

TPA (mg)

PL Q

Ys (

%)

I

10 50 100 150 200 250 3000

PL Q

Ys (

%)

120 150 180 200T (oC)

F

60

50

40

30

20

10

0

70

80

60

50

40

30

20

10

0

PL Q

Ys (

%)

G

0.05 0.1 0.2 0.4 0.6 0.8 1

70

AA (mL)

PL Q

Ys (

%)

120 150 180 200T (oC)

D 50

40

30

20

10

0

50

40

30

20

10

0

FA (mg)

PL Q

Ys (

%)

C

5 10 30 50 70 90 100

60

50

40

30

20

10

0

BA (mg)

PL Q

Ys (

%)

E

10 20 50 100 150 200

70

80yg-CQDs

PL Q

Ys (

%)

120 150 180 200T (oC)

H

60

50

40

30

20

10

0

70o-CQDs

b-CQDs c-CQDs

r-CQDs

g-CQDs

y-CQDs

dr-CQDs

b-CQDs c-CQDs

yg-CQDs o-CQDs

r-CQDs

Figure S4. Optical properties of the five selected CQDs. (A) PL spectra of the b-CQDs excited

at different wavelengths. (B) PL spectra of the c-CQDs excited at different wavelengths. (C) PL

spectra of the yg-CQDs excited at different wavelengths. (D) PL spectra of the o-CQDs excited at

different wavelengths. (E) PL spectra of the r-CQDs excited at different wavelengths. (F)

Corresponding PLE spectra of the five selected CQDs. (G) The relationship between the maximum

excitation wavelength and the corresponding excitonic absorption peak of the five selected CQDs.

(H) Photostability data for the b-CQDs under continuous irradiation with UV light for ten hours.

(I) Photostability data for the c-CQDs under continuous irradiation with UV light for ten hours. (J)

Photostability data for the yg-CQDs under continuous irradiation with UV light for ten hours. (K)

Photostability data for the o-CQDs under continuous irradiation with UV light for ten hours. (L)

Photostability data for the r-CQDs under continuous irradiation with UV light for ten hours. (M)

The temperature stability test of b-CQDs. (N) The temperature stability test of c-CQDs. (O) The

temperature stability test of yg-CQDs. (P) The temperature stability test of o-CQDs. (Q) The

temperature stability test of r-CQDs.


700300

PLE I

nte

nsity

(a. u.)

FPLE

T (oC)4025154

o-CQDs

PL Inte

nsity

(a. u.)

I t/I 0

(%)

0Time (h)

1 2 3 4 5 6 7 8 9 10

100

80

60

40

20

Jyg-CQDs

I t/I 0

(%)

0Time (h)

1 2 3 4 5 6 7 8 9 10

100

80

60

40

20

Ko-CQDs

I t/I 0

(%)

0Time (h)

1 2 3 4 5 6 7 8 9 10

100

80

60

40

20

Lr-CQDs

I t/I 0

(%)

0Time (h)

1 2 3 4 5 6 7 8 9 10

100

80

60

40

20

I

c-CQDs

Excito

nic

absorp

tion p

eak

(nm

)

350 400 450Maximum excitation w avelength (nm)

500 550 600

400

500

550

450

600

G

I t/I 0

(%)

0Time (h)

1 2 3 4 5 6 7 8 9 10

100

80

60

40

20

H

b-CQDs

Inte

nsity

(a. u.)

600 700Wavelength (nm)

E

800500

510530550570590

r-CQDs

Inte

nsity

(a. u.)


C

700 800

360380400420440

Inte

nsity

(a. u.)

300 400 500 600Wavelength (nm)

A

700

330350370390

Inte

nsity

(a. u.)


B

700 800

380400420440460

300

b-CQDs yg-CQDsc-CQDs

PL Inte

nsity

(a. u.)

4 15 25 40T (oC)

b-CQDs

T (oC)4025154

c-CQDs

PL Inte

nsity

(a. u.)

O

T (oC)4025154

yg-CQDs

PL Inte

nsity

(a. u.)

Inte

nsity

(a. u.)

500 600Wavelength (nm)

700

480500520540560

Do-CQDs

N PM

Q

T (oC)4025154

r-CQDs

PL Inte

nsity

(a. u.)

650

350

Figure S5. Bandgap energy levels of the five selected CQDs. (A) Ultraviolet photoelectron

spectroscopy data of b-CQDs. (B) Ultraviolet photoelectron spectroscopy data of c-CQDs. (C)

Ultraviolet photoelectron spectroscopy data of yg-CQDs. (D) Ultraviolet photoelectron

spectroscopy data of o-CQDs. (E) Ultraviolet photoelectron spectroscopy data of r-CQDs. (F)

Dependence of the HOMO and LUMO energy levels with respect to the particle size of the five

selected CQDs.

E

Inte

nsity (

Arb

. U

nits)

19 18 17Binging Energy (eV)

20 16 15

19.79 eV

Inte

nsity (

Arb

. U

nits)

6 2Binging Energy (eV)

10 0

2.42 eV

21 8 412 -2

r-CQDs

C

Inte

nsity (

Arb

. U

nits)


20 16 15

18.91 eV Inte

nsity (

Arb

. U

nits)


10 0

2.28 eV

21 8 412 -2

yg-CQDs

AIn

tensity (

Arb

. U

nits)


20 16 15

18.75 eV Inte

nsity (

Arb

. U

nits)


10 0

2.77 eV

21 8 412 -2

b-CQDs

D

Inte

nsity (

Arb

. U

nits)


20 16 15

19.98 eV

Inte

nsity (

Arb

. U

nits)


10 0

2.96 eV

21 8 412 -2

o-CQDs

Energ

y level (e

V)

1.7 1.8 1.9 2.0Lateral size (nm)

2.1 2.2 2.3 2.4 2.5

-3

-4

-2

-5HOMOLUMO

B

Inte

nsity (

Arb

. U

nits)


20 16 15

18.71 eV Inte

nsity (

Arb

. U

nits)


10 0

2.36 eV

21 8 412 -2

c-CQDs

F

Figure S6. Stability and structural characterizations of the w-CQDs. (A) Photostability data

for the w-CQDs under continuous irradiation with UV light for ten hours. (B) The temperature

stability test of w-CQDs. (C) XRD spectrum of the w-CQDs. (D) Raman spectrum of the w-CQDs.

(E) FT-IR spectrum of the w-CQDs. (F) XPS survey spectrum of the w-CQDs. (G) High-resolution

C1s spectrum of the w-CQDs. (H) High-resolution N1s spectrum of the w-CQDs. (I) High-

resolution O1s spectrum of the w-CQDs.

I t/

I 0(%

)

0Time (h)

1 2 3 4 5 6 7 8 9 10

100

80

60

40

20

280 285 290 295 300

Inte

nsity (

a.

u.)

Binding energy (eV)

C1s

C=C/C-C

C-N/C-O

C=O

G

-COOHC-O

4000 3000 2000 1000Wavenumber (cm-1)

Inte

nsity (

a.

u.)

O-H/N-H

C=C

E

T (oC)4025154

PL I

nte

nsity (

a. u.)

O1sN1s

C1s

0 200 400 600 800

Inte

nsity (

a.

u.)

Binding energy (eV)

F

395 405 410

N1s

Inte

nsity (

a.

u.)

Binding energy (eV)

NH2

H

400390

500 1000 1500 2000Raman shift (cm-1)

Inte

nsity (

a.

u.)

2500

DG

D

10 20 30 40 50 60 70

Inte

nsity (

a.

u.)

2 Theta (degree)80

CB

O1s

525 530 535 540 545

C=O

C-O

Inte

nsity (

a.

u.)

Binding energy (eV)

I

550

A

Figure S7. The applications of the CQDs. (A) Photographs of the CQDs doped PMMA composite

films under daylight. (B) Cytotoxicity of the o-CQDs toward HeLa cells. (C) Confocal bright field

image of HeLa cells incubated with o-CQDs. (D) Confocal fluorescence image of HeLa cells

incubated with o-CQDs excited at 405 nm. (E) Confocal fluorescence image of HeLa cells

incubated with o-CQDs excited at 488 nm. (F) Confocal fluorescence image of HeLa cells

incubated with o-CQDs excited at 543 nm.

Cell

Via

bility

(%

)

24 h 48 h100

80

60

40

20

020 40 60 80 100

[o-CQDs] (mg·L-1)

B

Cyan YellowYellow-green (YG) OrangeYellow+Green Green+Orange

Deep-red+BlueRed+Deep-redYG+Orange White

Blue Green

Red Cyan+Yellow+RedDeep-red （DR） Blue+YG+DR

25 μm 25 μm

C D

25 μm25 μm

E F

A

Table S1. The electron-withdrawing and electron-donating group ratios of the five selected

CQDs in XPS spectra and elemental analysis.

Samples b-CQDs c-CQDs yg-CQDs o-CQDs r-CQDs

XPS

C (%) 57.67 62.95 59.06 67.26 68.65

N (%) 14.77 14.51 13.11 11.95 8.69

O (%) 21.15 22.54 22.57 20.79 22.66

S (%) 6.41 — — — —

B (%) — — 5.26 — —

N/C 0.26 0.23 0.22 0.18 0.12

C=O 45.51 55.08 60.3 67.9 71.64

C-O 54.49 44.92 39.7 32.1 28.36

Elemental

analysis

C (%) 68.3 60.0 73.1 63.7 71.9

N (%) 20.2 16.6 17.1 13.4 12.4

H (%) 3.8 3.7 4.3 5.6 5.2

N/C 0.29 0.27 0.23 0.21 0.17

Table S2. PL scan conditions and QY data for the as-prepared CQDs.

Samples Excitation

(nm)

Emission

(nm)

PL range

(nm)

Quantum

yields (%)

b-CQDs 355 450 360-600 25

c-CQDs 410 490 410-620 36

g-CQDs 420 500 420-630 28

yg-CQDs 440 540 450-660 72

y-CQDs 470 550 480-670 45

o-CQDs 535 600 540-690 59

r-CQDs 600 665 550-750 47

dr-CQDs 640 700 650-760 52

w-CQDs 360 560 370-800 39

Table S3. The PL lifetimes and energy levels of the five selected CQDs.

Samples b-CQDs c-CQDs yg-CQDs o-CQDs r-CQDs

PL

lifetimes

λex (nm) 355 410 440 535 600

λem (nm) 450 490 540 600 665

A1 2350.72 2444.23 2980.54 4303.28 6125.37

t1 (ns) 10.91 7.87 4.50 3.08 2.49

R2 0.994 0.987 0.988 0.991 0.990

Energy

levels

HOMO (eV) -5.22 -4.85 -4.57 -4.18 -3.83

LUMO (eV) -2.46 -2.32 -2.23 -2.18 -1.95

λedge (nm) 450 490 530 620 660

Egopt (eV) 2.76 2.53 2.34 2.00 1.88

Supplementary Materials for · Figure S2. Structural characterizations of the five selected...

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