Regulation of physicochemical characteristics on surface of SiC quantum dots and its optical properties

One-step effective regulation of physicochemical characteristics on the surface of SiC quantum dots (QDs) was obtained by a chemical coupling method via the adjustment of the component and relative content of etchant. The results indicate that the aqueous SiC-QDs are prepared with SiC nanoparticles etched in a mixed chemical etchant of nitric acid (HNO3) and hydrofluoric acid (HF) via ultrasonic cavitation dispersion and high-speed centrifugal treatment. Some hydrophilic organic functional groups, such as carboxyl (-COO), hydroxyl (-OH) and so on, on the surface of SiC-QDs are formed in the process of fabrication. In addition, hydrosulphonyl (-SH) is also prepared via one-step for sulfuric acid (HNO3) as a coupling reagent and the addition of the mixed acid (i.e., HF and HNO3). The component and relative content of mixed-acid etchant can affect the hydrosulphonyl formation and photoluminescence (PL) intensity. The results show that the maximum light intensity of SiC-QDs is emitted at a 340 nm exciting light wavelength, and the PL intensity decreases with increasing the content of H2SO4. The aqueous SiC-QDs surface prepared can be stable and coupled with -SH, thus obtaining a high photoluminescence strength, when the volume ratio of H2SO4 to HNO3 is 1:1 (i.e., V(HF):V(HNO3):V(H2SO4)= 6:1:1). In addition, the regulation of physicochemical characteristics on the surface of SiC-QDs and the formation mechanism are also analyzed. ©, 2015, Chinese Ceramic Society. All right reserved.