One-pot hydrothermal synthesis of carbon dots-immobilized hydrozincite for ZnO-based nanocomposite lighting applications

The immobilization of fluorescent nanomaterials in host-guest systems is one of the important factors for the further development of light-emitting properties in nanocomposite materials. In this study, one-pot hydrothermal synthesis was performed to generate advanced fluorescent nanocomposite by immobilizing carbon dots (C-dots) in a layered hydrozincite matrix while synthesizing them in a reaction solution. The one-pot reaction was performed by hydrothermal treatment starting from zinc acetate, urea, and diammonium hydrogen citrate in solution as precursor. The reaction condition that C-dots and hydrozincite could be synthesized together in a one-pot hydrothermal reaction at 200°C was investigated by adjusting the pH of the precursor, and the formation criteria depending on the pH were discussed. Based on the changes in crystal structure and in the surface state of the resulting composite powder compared with the single hydrozincite powder, the interaction that contributed to the immobilization of carbon dots was discussed. The fluorescence properties of the C-dots immobilized zinc compounds were characterized. Further sintering under an appropriate condition for the C-dots-hydrozincite composite allowed conversion into the C-dots-zinc oxide composite exhibiting quite different fluorescent characteristics.