Size-controlled and large-scale synthesis of organic-soluble Ag nanocrystals in water and their formation mechanism

• Published in: Progress in natural science Vol. 21; no. 6; pp. 447 - 454
• Main Authors: SHI, Yu-yuan, SUN, Bin, ZHOU, Zhe, WU, Yong-tao, ZHU, Mei-fang
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.12.2011
• Subjects: formation; formation mechanism; large-scale; mechanism; nanocrystals; organic-soluble; organic-soluble Ag nanocrystals; size-controlled; synthesis; synthesis; formation mechanism; size-controlled; large-scale; organic-soluble Ag nanocrystals
• ISSN: 1002-0071
• DOI: 10.1016/S1002-0071(12)60081-1

Organic-soluble Ag nanocrystals（NCs） with tunable sizes in the range from 5.4 to 22.1 nm were synthesized by a facile, reproducible and easily scaled up route using water as solvent in the presence of oleic acid and an alkylamine.The synthetic Ag NCs exhibits excellent hydrophobicity and can be well re-dispersed in various non- or weak-polar media.The tunable sizes of the Ag NCs were achieved by simply adjusting the initial precursor AgNO3 concentration.Large-scale synthesis of the Ag NCs was realized at a high AgNO3 concentration（0.4 mol/L）.As much as 16.2 g highly uniform organic-soluble Ag NCs with 5 nm average diameter can be readily synthesized at low cost in a single reaction only using 400 mL water as solvent,which is adaptable to the industrial scale production.The structure of the obtained Ag NCs was investigated in detail by X-ray diffractometry,transmission electron microscopy,Fourier transform infrared and thermal gravimetric analysis measurements.The results reveal that the surface of the organic-soluble Ag NCs is coated with the monolayer surfactants consisting of oleic acid and the alkylamine.In addition,on the basis of the sufficient evidences,a proposed mechanism based on the "bilayer surfactant-controlled reaction" successfully demonstrates the formation of high quality organic-soluble Ag NCs in the aqueous solution.