Cost-effective, hydride-free aqueous synthesis of CdTe quantum dots enabled by using ammonia as the reducing agent

• The synthesis of highly fluorescent CdTe quantum dots is demonstrated. • Ammonia is used to reduce sodium tellurite in lieu of conventional hydride. • The emission color of quantum dots is facile controlled over green–red region. The development of a simple, cost-effective, and green method to synthesize CdTe quantum dots (QDs), which are a key nanomaterial in sensing, bioimaging, and immunofluorescence analysis is highly desirable. In this study, we used ammonia in lieu of common hydride reductant to synthesize CdTe QDs by simple refluxing aqueous solutions of cadmium salt, sodium tellurite , and 3-mercaptopropionic acid (MPA). The obtained CdTe QDs were characterized by absorption and photoluminescent spectroscopies, X-ray diffraction (XRD), and transmission electron microscope (TEM). The absorption window and the emission color of QDs were facile controlled over the green–red range by varying the refluxing time. As the QD size increased the crystal structure transformed from CdTe to a CdTeS alloyed form. The results demonstrated herein suggest a cost-effective method for production of CdTe QDs.