Controllable synthesis of novel luminescent CuFeS2 quantum dots with magnetic properties and cation sensing features

Since Cu2+ and Fe3+ ions have been considered as bioactive cations in oxygen transport and enzymatic reactions, the development of reliable ways for the monitoring of the two species will be highly desirable. But the optical stability of conventional organic chromophores needs to be improved. Therefore, the employment of quantum dots (quantum dots are abbreviated to be QDs) such as ternary CuFeS2 QDs for the purpose of sensing has been reported in this study. CuFeS2 QDs were synthesized by using oleylamine as the stabilizer at 180 °C and the particle size was around 2–3 nm. The monodispersed quantum dots with tetragonal chalcopyrite crystalline structure were identified. The corresponding excitation and emission wavelengths of the QDs were monitored at 372 and 458 nm. Magnetic properties were analyzed via applied magnetic field ranging between −6000 and 6000 Oe at 300 K and the ferromagnetic phase was verified. In this report, CuFeS2 QDs has been used as an optical probe to detect the metal ions with high sensitivity, selectivity and fast responses. Two linear equations can be obtained in the range from 0 to 30 μM for Cu2+ and from 0 to 45 μM for Fe3+ (detection limits: Cu2+, 1.98 μM; Fe3+, 2.15 μM). These results may provide promising applications in cation sensing fields.