Supporting Information

Ultra-weak chemiluminescence enhanced by facilely synthesized

nitrogen-rich quantum dots through chemiluminescence resonance

energy transfer and electron hole injection

Yongzan Zheng, Dingkun Zhang, Syed Niaz Ali Shah, Haifang Li, and Jin-Ming Lin*

Beijing Key Laboratory of Microanalytical Methods and Instrumentation, Department of Chemistry, Tsinghua University, Beijing 100084, People’s Republic of China

Experimental Section

Reagents. All chemicals used were of analytical grade. Hydrogen peroxide

(H2O2), sodium azide (NaN3), thiourea, and sodium hydroxide (NaOH) were obtained

from Beijing Chemical Reagent Co. (Beijing, China). 5-aminotetrazole and ascorbic

acid were bought from J&K Scientific Ltd. Sodium periodate (NaIO4) was received

from XI LONG Chemical Co. Ltd. (Guangzhou, Chian) Nitro blue tetrazolium

chloride (NBT) was from Nacalai Tesque Inc. (Tokyo, Japan). 5, 5-Dimethyl-1-

pyrrolineN-oxide (DMPO) was purchased from Tokyo Kasei Kogyo Co. Ltd. (Tokyo,

Japan). Dicyandiamide and 2, 2, 6, 6-Tetramethyl-4-piperidine (TEMP) were bought

from Sigma Aldrich (St. Louis, MO, USA). All chemicals were used as received

without further purification, and deionized water was used in all experiments.

Apparatus. Batch CL experiments were carried out with a BPCL luminescence

analyzer (Institute of Biophysics, Chinese Academy of Sciences, Beijing, China).

Fluorescence spectra and CL spectra were measured with a fluorescence

spectrophotometer (F-7000, Hitachi, Japan). ESR spectra were measured on a Bruker

Electronic Supplementary Material (ESI) for ChemComm.This journal is © The Royal Society of Chemistry 2017

spectrometer (ESP-300E, Bruker, Germany). Transmission electron microscopy

(TEM) images were recorded by an electron microscope operating at 100 kV (JEM-

2010, JEOL, Japan). The Fourier Transform Infrared (FTIR) spectrum was obtained

with FTIR spectrometer (Massachusetts, USA). The X-ray photoelectron spectrum

(XPS) was measured by a PHI Quantera SXMTM Scanning X-ray MicroprobeTM

using Al-Kα as the exciting source (1486.6eV).

Synthesis of N-dots. First, 0.1031 g of 5-aminotetrazole was dissolved to 20

mL deionized water. After stirring of 20 min, the solution was transferred to a 30 mL

Teflon-lined stainless steel autoclave. Then the autoclave was put into a Muffle

furnace, heating at 200 ℃ for 10 h. After the furnace cool to room temperature N-dots

was obtained.

Scheme 1 The schematic mechanism for the formation of N-dots

Fig. S1 The fluorescence spectra of N-dots with the excitation wavelengths increasing,

the N-dots synthesized with different heating condition: (a) 200 ℃10 h, (b) 200 ℃ 20

h.

Fig. S2 The XPS survey of N-dots, the N-dots synthesized with different heating time

Fig. S3 The FTIR spectra of 5-aminotetrazole and N-dots, the N-dots synthesized with different heating time.

Fig. S4 The image of the color change in the NaIO4-H2O2 system with N-dots and without N-dots

Fig. S5 The kinetic curves of N-dots-NaIO4-H2O2 CL system with different radical scavengers (NBT, NaN3, thiourea, ascorbic acid and DMPO). The concentration of N-dots, NaIO4, H2O2, were 1.2mg/ml, 10-2 M, and 10-3 M, respectively.

Table S1 Effects of radical scavengers on N-dots-NaIO4 -H2O2 CL system

Radical scavengers Concentration (M) CL intensity of N-dots-NaIO4 -H2O2 (Count)

H2O 30781

1.0×10-2 3629

1.0×10-3 16053NBT

1.0×10-4 24388

1.0×10-1 3629

1.0×10-2 21343NaN3

1.0×10-3 30610

1.0×10-2 1442

1.0×10-3 11690Thiourea

1.0×10-4 27233

1.0×10-1 2725

1.0×10-2 10824Ascorbic acid

1.0×10-3 26690

1.0×10-1 1685

1.0×10-2 8893DMPO

1.0×10-3 16070

Fig. S6 The kinetic curves of N-dots-NaIO4-H2O2 CL system, the solution was bubbled with O2 (red) or N2 (blue) for 20 min before injecting.