Quantum dots, each having a core comprising CdTe and a shell comprising GSH covering the core, are provided. The Quantum dots can be formed in a solution comprising a telluride (Te) precursor and a cadmium (Cd) precursor for forming the cores, and glutathione (GSH) for forming shells covering the cores. The cores can comprise CdTe nanocrystals grown in the solution. The growth of the nanocrystals can be limited. The quantum dots can have high fluorescence emission quantum yield such as up to about 45%, and small sizes such as from about 3.8 nm to about 6 nm.