Room-temperature solid-state reaction to tree-like fractal nano-CdS and third-order nonlinear optical properties

A novel tree-like nano-cadmium sulfide (CdS) with the fractal feature is synthesized by solid-state reaction at room temperature from complex precursor with aminotrimethylenephosphonic acid (ATMP) as ligand. The obtained sample is the crystalline cubic beta cadmium sulfide. The tree is composed of nanorods with an average diameter of ca. 95 nm and a length of up to 100-650 nm. The nanorods grow in the asymmetrical "Y" shape. The amount of ATMP plays an important role in the formation of fractal structure. Nonlinear optical (NLO) measurements by the Z-scan technique exhibit that the tree-like fractal nano-CdS has the third-order nonlinear optical properties of both NLO absorption and NLO refraction with self-focusing effect and the optical limiting performance.