A new sulfur-doped source and synergistic effect with nitrogen for carbon dots produced from glucose<xref rid="cpb_28_12_128102fn1" ref-type="fn">*</xref><fn id="cpb_28_12_128102fn1"><label>*</label><p>Project by the National Natural Science Foundation of China (Grant Nos. 51571085, 11805052, and 61705062), the Research Project for Basic and Forefront Technology of Henan Province, China (Grant No. 162300410219), and the Doctor Foundation of Henan Polytechnic University, China (Grant No. B2014049).</p></fn>

A new sulfur-doped source and synergistic effect with nitrogen for carbon dots produced from glucose**

Project by the National Natural Science Foundation of China (Grant Nos. 51571085, 11805052, and 61705062), the Research Project for Basic and Forefront Technology of Henan Province, China (Grant No. 162300410219), and the Doctor Foundation of Henan Polytechnic University, China (Grant No. B2014049).

Fu Lige¹, Yin Yuehong^{1, †}, Cao Guohua^{1, ‡}, Wu Pingping¹, Wang Jian¹, Yan Lingling¹, Zhang Baoqing², Li Ming¹

(a) Fluorescence emission spectrum of N, S-CDs with various pH from 3 to 13; the insert is the photos under pH 3 and 13, respectively. (b) PL intensity upon the cyclic switching of N, S-CDs under alternating conditions of pH = 3 and pH = 13.