One-pot solvothermal synthesis of uniform layer-by-layer self-assembled ultrathin hexagonal Gd2O2S nanoplates and luminescent properties from single doped Eu3+ and codoped Er3+, Yb3+

Uniform Gd2O2S flower-like nano-assemblies were prepared through one-pot mild solvothermal synthesis. The parallel nanoplates are the building blocks, similar to 3 nm in thickness and 20-30 in diameter. Ethanediamine, the main solvent, plays an important role in dissolving a large amount of sulphur and producing active S2- ions, which results in the direct formation of Gd2O2S. Oleylamine, the capping agent, controls the growth of the plate-like structure. Under UV excitation, the Gd2O2S:Eu3+ nano-phosphor shows good red luminescence with a main emission peak at 627 nm. Under 980 nm laser excitation, Gd2O2S:xYb(3+), 1%Er3+ nano-phosphors exhibit a tuneable emission, shifting from greenish-yellow to orange-yellow, with increasing Yb3+ content.