银纳米线的自组装合成详解
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▪ “soft” templates: The silver nanowires synthesized using these templates were
often in the form of aggregated bundles, and the templates also needed to be removed in order to recover the individual nanowires.
Nitrate Ion ——Growth Mechanism for Ag nanowires
(a) AgClO4
(b)AgNO3
Other anions, such as
ClO4−, B2O72−, NO2−,CO32−, HPO42−, SO42-, only Ag nanoparticles were formed.
▪ Templateless (avoid the step of template removal) : The products of these
templateless methods were, however, often characterized by problems such as relatively low yields, irregular morphologies, polycrystallinity, and low aspect ratios.
Properties of Ag nanowire
1、Transparent conductive electrode （a promising substitute of ITO films） 2、As a substrate for Surface enhanced Raman scattering 3、Unique template for novel nanostructures and functional nanomaterials （Yugang Sun,Nanoscale, 2010, 2, 1626–1642）
Polyol Processes
1000
Self-assemble Ag Nanowires by Polyol Process
Schematic Illustration of The Process
Main Chemicals and Their Roles EG: solvents and reductants (Ethylene glycol) Pt Seeds : nuclei for the epitaxial growth of silver. PVP: polymeric surfactants. AgNO3: Ag sources, while nitrates are uncertain.
Anions molecular geometry
Chien Lin Kuo and Kuo Chu Hwang. Langmuir. 2012, 28, 3722−3729
Polyol Processes
▪ Xia and co-workers synthesized silver nanowires in high yields by reducing AgNO3 with EG heated to 148 ℃in the presence of PVP and a trace amount of NaCl, CuCl2 or CuCl.
▪ Its side surfaces are tightly passivated by PVP while its ends remain reactive toward the arriving silver atoms.
Polyol Processes
▪ The additives, such as CO32− and NH3, resulting from the dissociation of (NH4)2CO3, have the ability to accelerate the oxidative dissolution of silver.
anions
CO3 2− ClO4−, HPO42−, SO42-
B2O72−, NO2− NO3-
sp2 Central ‘+’ charge
YES
NO
NO
NO
NO
NO
YES
YES
NO3-
●sp2 triangular planar
configuration ●a positive charge at N
Results of TEM image and XRD patterns
Diameter: 30-40nm Lengths: ～50μm
With FCC phase
Yugang Sun,Yadong Yin,Brian T, Mayers,Thurston Herricks, Younan Xia. Chem. Mater. 2002, 14, 4736-4745
The Self-Assemble SynthBiblioteka Baidusis of Ag Nanowires
蒋莉 谷穗 易娜 程若霖 宛刚 邓健 陆翔 张云龙
Content
Introduction
Self-assemble Ag Nanowires by Polyol Process
Three-Phase-Interface Self-Assembly Process Conclusion
Approaches for the Production of Ag Nanowires
▪ “hard” templates:These templates were effective in fabricating nanowires
with uniform and controllable dimensions, many of them needed to be selectively dissolved under harsh conditions in order to harvest the nanowires.
often in the form of aggregated bundles, and the templates also needed to be removed in order to recover the individual nanowires.
Nitrate Ion ——Growth Mechanism for Ag nanowires
(a) AgClO4
(b)AgNO3
Other anions, such as
ClO4−, B2O72−, NO2−,CO32−, HPO42−, SO42-, only Ag nanoparticles were formed.
▪ Templateless (avoid the step of template removal) : The products of these
templateless methods were, however, often characterized by problems such as relatively low yields, irregular morphologies, polycrystallinity, and low aspect ratios.
Properties of Ag nanowire
1、Transparent conductive electrode （a promising substitute of ITO films） 2、As a substrate for Surface enhanced Raman scattering 3、Unique template for novel nanostructures and functional nanomaterials （Yugang Sun,Nanoscale, 2010, 2, 1626–1642）
Polyol Processes
1000
Self-assemble Ag Nanowires by Polyol Process
Schematic Illustration of The Process
Main Chemicals and Their Roles EG: solvents and reductants (Ethylene glycol) Pt Seeds : nuclei for the epitaxial growth of silver. PVP: polymeric surfactants. AgNO3: Ag sources, while nitrates are uncertain.
Anions molecular geometry
Chien Lin Kuo and Kuo Chu Hwang. Langmuir. 2012, 28, 3722−3729
Polyol Processes
▪ Xia and co-workers synthesized silver nanowires in high yields by reducing AgNO3 with EG heated to 148 ℃in the presence of PVP and a trace amount of NaCl, CuCl2 or CuCl.
▪ Its side surfaces are tightly passivated by PVP while its ends remain reactive toward the arriving silver atoms.
Polyol Processes
▪ The additives, such as CO32− and NH3, resulting from the dissociation of (NH4)2CO3, have the ability to accelerate the oxidative dissolution of silver.
anions
CO3 2− ClO4−, HPO42−, SO42-
B2O72−, NO2− NO3-
sp2 Central ‘+’ charge
YES
NO
NO
NO
NO
NO
YES
YES
NO3-
●sp2 triangular planar
configuration ●a positive charge at N
Results of TEM image and XRD patterns
Diameter: 30-40nm Lengths: ～50μm
With FCC phase
Yugang Sun,Yadong Yin,Brian T, Mayers,Thurston Herricks, Younan Xia. Chem. Mater. 2002, 14, 4736-4745
The Self-Assemble SynthBiblioteka Baidusis of Ag Nanowires
蒋莉 谷穗 易娜 程若霖 宛刚 邓健 陆翔 张云龙
Content
Introduction
Self-assemble Ag Nanowires by Polyol Process
Three-Phase-Interface Self-Assembly Process Conclusion
Approaches for the Production of Ag Nanowires
▪ “hard” templates:These templates were effective in fabricating nanowires
with uniform and controllable dimensions, many of them needed to be selectively dissolved under harsh conditions in order to harvest the nanowires.