Synthesis, characterisation and nonlinear optical properties of stable PbS nanoclusters

Quantum confinement effects in low-dimensional semiconductors influence the optical properties, rendering them excellent candidates for device applications in Photonics. This paper presents our recent results on the synthesis of stable optical quality films of PbS nanoclusters by a colloidal chemistry method in the size range of few nanometers using lead acetate and sodium sulphide as the precursors. Optical absorption spectra reveal large signature blue shift from the bulk absorption cutoff wavelength. Optical Nonlinearity induced in PbS nanoclusters at low power continuous wave laser excitation is studied by the z-scan method. The origin of the obtained nonlinearity is analysed in terms of thermal variation of refractive index.