PbS–polymer nanocomposite with third-order nonlinear optical response in femtosecond regime

• Published in: Materials letters Vol. 51; no. 6; pp. 461 - 469
• Main Authors: Liu, Bing, Li, Heping, Chew, Chwee Har, Que, Wenxiu, Lam, Yee Loy, Kam, Chan Hin, Gan, Leong Ming, Xu, Guo Qin
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.12.2001; Elsevier
• Subjects: Applied sciences; Composites; Exact sciences and technology; Forms of application and semi-finished materials; HRTEM; Microemulsion; Nanocomposite; Nonlinearity; PbS; Polymer industry, paints, wood; Polymerisation; Technology of polymers; Z-scan; PbS; Polymerisation; Z-scan; Nonlinearity; Nanocomposite; Microemulsion; HRTEM; Emulsion copolymerization; Dispersion degree; Non linear optics; Experimental study; Methyl methacrylate copolymer; Crosslinked copolymer; Acrylonitrile copolymer; Morphology; Optical properties; Preparation; Lead II Sulfides; Optical material; Radical copolymerization
• ISSN: 0167-577X; 1873-4979
• DOI: 10.1016/S0167-577X(01)00336-6

A new method is developed using polymerized bicontinuous microemulsions to synthesize PbS–polymer nanocomposite having large nonlinear optical response. Besides a polymeric nonionic surfactant, ω-methoxy poly(ethylene oxide) 40 undecyl-α-methacrylate (C 1-PEO-C 11-MA-40), a system consisting of methyl methacrylate (MMA), acronitrile (AN), ethylene glycol dimethacrylate (EGDMA), aqueous solutions of Pb(NO 3) 2/thioacetamide (TAA) was selected. High-resolution transmission electron microscopy (HRTEM) results indicated PbS nanocrystals with a width of 5 nm and a cubic structure is formed in water domains. A single-beam Z-scan measurement showed that the nanocomposite polymer has a nonresonant and negative nonlinear refractive index ( γ) of 6.8×10 −12 cm 2/W at 780 nm. The origin of the large nonlinear optical response based on the contribution of surface recombination owing to high surface-to-volume ratios of PbS nanoparticles to the optical nonlinearity is discussed.