The optical behavior of multi-emission quantum dots based on Tb-doped ZnS developed via solvothermal route for bioimaging applications

摘要

Quantum dots (QDs), semiconducting nanocrystals with exceptional photo-physical characteristics, have become one of the prevailing class of multifunctional nanodevices and imaging probes. The engineering of QD probes became an essential step for successful clinical applications in real-life. In this work, a water soluble and highly luminescent semiconducting QDs are developed via solvothermal route. Terbium was used as a dopant to replace the Zn in the ZnS nanocrystals. Various concentrations of Tb, from 0 to 6 at.%, was doped into the ZnS. The influence of Tb dopant on the crystal structure of the ZnS and diameter of the formed nanocrystals was investigated using X-ray diffraction and transmission electron microscopy. The optical properties were studied using the UV-vis spectrophotometer, which showed a red shift of the optical band gap. The luminescence properties showed that the doping of ZnS with 6at.% of Tb ions resulted in a remarkable enhancement of the luminescence intensity and the quantum yield. This sample showed three distinctive light emissions (blue, green and red) when excited at 320 nm, 360 nm and 390 nm. The obtained results embarked that the developed QDs may be employed as efficient bio-imaging probe for practical clinical applications in real-life, which is confirmed in this article for the first time.