Nonlinear Optical Properties of PbS Colloidal Quantum Dots Fabricated via Solvothermal Method

Abstract

Lead sulfide (PbS) quantum dots were prepared by a solvothermal method. The as-synthesized quantum dots were dispersed by toluene, n-hexane, and tetrachloromethane separately and characterized by high-resolution transmission electron microscopy. Femtosecond laser pulse-based single-beam Z-scan analysis was employed to investigate the third-order nonlinear optical response of the quantum dots. Dispersants used in the fabrication process play the essential role not only in the nucleation and crystallization of the nanoparticles but also in modifying the nonlinear optical responses of PbS colloidal quantum dots. Additionally, laser power of the detecting beam has a major influence on the accuracy of single-beam Z-scan analysis.