ẢNH HƯỞNG CỦA NHÓM CHỨC QUANG HỌC TRÊN BỀ MẶT ĐẾN TÍNH CHẤT QUANG CỦA CHẤM LƯỢNG TỬ CARBON

Carbon quantum dots (CQDs) have been increasingly investigated as alternative materials for CdSe QDs due to its visible luminescence and non-toxic properties. Controversially proposed structure of CQDs includes three components: (1) polycyclic aromatic hydrocarbon of different sizes (PAH), (2) surface fluorophore and (3) solubility determinant groups. However, the formation and the effects of fluorophore on the optical properties of CQDs are yet explored. Herein, we firstly synthesized acid functionalized CQDs and then post treated them with ethylenediamine (EDA). The structure and optical properties of the two types of CQDs were characterized by transmission electron microscope (TEM), infrared spectroscopy (FT-IR), UV-Vis absorption and photoluminescence (PL) spectroscopy. It revealed that fluorophore groups which are derivatives of citrazinic acid were formed on the surface of CQDs. The fluorophore groups created an absorption band centered at 346 nm and especially enhanced the PL quantum yield from 14 to 38%. The results demonstrated herein show evidently the effects of fluorophore on the optical properties of CQDs.