Photoluminescence Stability Enhancement of Ag–In–Ga–S/GaSx Core/Shell Quantum Dots with Thicker Shells by the Addition of Gallium Diethyldithiocarbamate

A spectrally narrow band edge emission is generated in the green region from cadmium-free quantum dots comprised of silver indium gallium sulfide coated by gallium sulfide shells. The thickness of the gallium sulfide shell is increased by using gallium tris(diethyldithiocarbamate) as a supplementary precursor showing a strong adhesion with the quantum dot cores. Photoluminescence intensity and spectral shape of the core/shell quantum dots with the thicker shells are unchanged after 90 days. An introduction of gallium diethyldithiocarbamate as a supplementary precursor for the synthesis of gallium sulfide shells increases the thickness of coatings. The stablility of green emission from silver indium gallium sulfide/gallium sulfide core/shell quantum dots is significantly improved.