Facile Synthesis of near-Infrared-Emitting Water-Dispersed CdHgTe/CdS/ZnS Core/Shell/Shell Quantum Dots

We report the synthesis and characterization of highly luminescent quantum dots consisting of CdHgTe cores protected with double inorganic shells (core−shell−shell quantum dots). The outer ZnS shell provides efficient confinement of electron and hole wave functions inside the quantum dots as well as high photochemical stability. Introducing the middle shell sandwiched between CdHgTe core and ZnS outer shell allows considerable reducing strain inside nanocrystals because CdS had the lattice parameter intermediate to those of CdHgTe and ZnS. Preferential growth of the middle CdS shell in one crystallographic direction allows engineering the shape and luminescence polarization of the core−shell−shell quantum dots.