Mechanism of Elemental Superdoping of Low-Dimensional Carbon Materials

Elemental superdoping of low-dimensional carbon materials (CMs), which is realized by fluorination, followed by thermal defluorination in dopant sources, has been widely used to optimize many physical and chemical properties for various applications. The superdoping mechanism proposed previously is that fluorine adatoms on pristine carbon networks prefer to form clustered fluorine patterns, and thermal defluorination of such patterns would create high-concentration and concentration-adjustable divacancies, which stimulates high-level and level-adjustable doping. Here, we clarify that the mechanism is that (i) for pristine carbon networks, dispersed fluorine chains dominate the fluorine patterns and thermal defluorination of such patterns would not create carbon vacancies and superdoping is inapplicable, while (ii) for defective carbon networks, fluorine clusters dominate the fluorine patterns and both fluorination- and thermal defluorination-created carbon vacancies are present and jointly contribute to superdoping. This clarification is favorable to the engineering of elemental superdoping of CMs to optimize their various performances for many applications.