Lead sulfide colloidal nanocrystals with strong optical nonlinearity

Colloidal PbS nanocrystals have been synthesized by a developed procedure. UV–Vis absorption and Z-scan technique was also applied to study the nonlinear optical properties of prepared lead sulfide nanocrystals at 532 nm wavelength. The nonlinear refractive (n 2 ) and absorption ( β ) were determined which are confirming the strong nonlinearity at 532 nm of colloidal PbS nanocrystals. The obtained results have not been reported before. In this study, only a weak thermal optical nonlinearity was observed and the dominating nonlinear response is resulted by the electronic origin. The nonlinear optical properties of prepared sample supported wide applications in nanophotonics.