Fluorescent carbon nanoparticles from Chinese ink

Abstract

<p indent="0mm">Chinese ink has been widely used and preserved due to its unique color stability, diversity and uniformity, and has recently been proved to be an excellent source of carbon particles. Here, we prepared a series of carbon nanoparticles with different luminescent properties from Chinese ink, which offered a new method for preparing carbon quantum dots. The particle size and luminescence properties of carbon quantum dots were systematically investigated. We identified carbon quantum dots (CQDs) with a diameter of <sc>5–7 nm</sc> in the supernatant of the lampblack “ziyuguang”, and the fluorescence emission of CQDs was characteristic of excitation wavelength dependence, which provided the evidence for the presence of shining purple jade light in this “ziyuguang” stick. More than seven kinds of CQDs with different fluorescence properties were separated <italic>via</italic> polyacrylamide gel electrophoresis (PAGE) after oxidizing the raw soot. The fluorescence emission of lanes 1–7 ranged from 350 to <sc>670 nm,</sc> covering the whole visible light region of red, orange, yellow, green, blue, purple. The size distribution of CQDs was uniform, and the fluorescence emission spectrum was excitation independent, implying the uniform size and the simple and single interfaces. It is thus expected that high-quality CQDs can be produced on a large scale by exploiting the China’s ink capacity, laying the foundation for its application in various fields. Considering the long history and large-scale production capacity of Chinese ink production process, this provides a new way for large-scale, high-throughput preparation of CQDs with uniform size and stable fluorescence properties.