Preparation of Carbon Nanodots with Ultraviolet Emission by Pulsed Laser Ablation
Minjie Yang, Jian-Xuan Shi, Ying Yin, Chuan‐Guo Shi
Abstract
To date, it is still a challenge to acquire carbon nanomaterials with ultraviolet (UV) emission due to the trapping of excited carriers by defect states and surface groups. Herein, a pulsed laser ablation (PLA) method without any post‐treatments is developed to prepare carbon nanodots (CNDs). The cores of the resulting CNDs are graphitic carbon with negligible defects, whereas the surfaces are passivated by simple oxygen‐related groups, which is demonstrated by high‐resolution transmission electron microscope (HRTEM) image, X‐ray diffraction (XRD) pattern, and Raman spectra. Thus, the trapping of excited carriers by defect states and surface groups is substantially suppressed. As a consequence, the CNDs exhibit inherent UV emission of carbon nanostructures. The excitation‐independent UV emission peak contains three sub‐bands at 305, 325, and 335 nm. This work develops an approach for the preparation of UV‐emissive CNDs, which expands the applications of CNDs to UV‐related areas.