Synthesis of nanocomposites Ho2O3/GQD and the effect of oxygen vacancies on its fluorescence and magnetic properties

In this paper, three kinds of nano-composites (Ho 2 O 3 /GQD, Ho 2 O 3 /N-GQD, Ho 2 O 3 /N,S-GQD) were prepared by hydrothermal synthesis, and their fluorescence and magnetic properties were characterized. The results show that elemental doping could promote the electronic Cπ-Nπ∗ leaps. In the composite process of Ho 2 O 3 and GQD or doped GQD, Ho and C are connected by O to form a new HO-O-C covalent bond. Compared with Ho 2 O 3 /GQD, the fluorescence intensity of Ho 2 O 3 /N-GQD and Ho 2 O 3 /N,S-GQD increased by 26.9 % and 61.4 % respectively, The magnetization of Ho 2 O 3 /N-GQD (VO1) (2.84emu/g) is slightly higher than that of Ho 2 O 3 /GQD (2.05emu/g). The magnetization of Ho 2 O 3 /N,S-GQD (VO2) is 3.09emu/g, about 1.5 times that of Ho 2 O 3 /GQD. After 2 h and 4 h of ultrasonic vibration treatment, the magnetic properties of doped Ho 2 O 3 /GQD were significantly improved due to the increase of oxygen-vacancy induced activation sites.