Synthesis and Characterization of Crystalline Ag ₂ Se Nanowires Through a Template‐Engaged Reaction at Room Temperature

Abstract

Single‐crystalline Ag2Se nanowires have been successfully synthesized through a template‐engaged topotactic reaction in which nanowires of trigonal selenium were transformed into Ag2Se by reacting with aqueous AgNO3 solutions at room temperature (RT). An interesting size‐dependent transition between two crystal structures has also been observed for this newly synthesized one‐dimensional system: The Ag2Se nanowires adopted a tetragonal structure when their diameters were less than ∼40 nm; an orthorhombic structure was found to be more favorable as the diameter of these nanowires was increased beyond 40 nm. Since this reaction can be carried out at ambient pressure and temperature, it should be straightforward to scale up the entire process for the high‐volume production of Ag2Se nanowires with well‐controlled sizes and crystal structures. These highly uniform nanowires of single‐crystalline Ag2Se are potentially useful as photosensitizers, superionic conductors, magnetoresistive compounds, or thermoelectric materials. This work also represents the first demonstration of a template‐engaged process capable of generating single‐crystalline nanowires from the solution‐phase and at RT.

Syringe pump-assisted synthesis of water-soluble cubic structure Ag2Se nanocrystals by a cation-exchange reaction

“…In recent years, a series of Ag 2 Se nanomaterials and the corresponding synthetic protocols have been reported in some literatures, such as the synthesis of nanoparticles by sonochemical methods [10][11][12], light-assisted preparation of various nanostructures and morphologies [13][14][15][16][17][18] of nanowires [2,19], Ag@Ag 2 Se core/shell structures [20], cationexchange methods for producing cubic structure nanoparticles at room temperature [21], obtaining nanocrystals with a well-defined shape by decomposition of the precursor [22], and so on. However, since the phase transition between α-Ag 2 Se and β-Ag 2 Se is reversible, Ag 2 Se generally exists in the β phase (orthorhombic structure) below 406 K. To date, most research has been focused on Ag 2 Se nanomaterials with orthorhombic structure (β-Ag 2 Se), and little on those with cubic structure (α-Ag 2 Se).…”

Ag2Se complex nanostructures with photocatalytic activity and superhydrophobicity

“…β-Ag 2 Se is used as a photosensitizer in photographic films and in thermochromic materials due to its relatively high Seebeck coefficient, low lattice thermal conductivity, and high electrical conductivity [6], while α-Ag 2 Se, being a superionic conductor, finds application in solid electrolytes in photochargable secondary batteries [7]. Various shapes of Ag 2 Se nano-and microstructures have been obtained by different methods, such as a solution-phase synthesis approach [5], a sacrificial template route [8], a template-engaged reaction method [9], and a hydrothermal route [10]. The study of possible industrial applications of such nanomaterials has also received tremendous attention.…”

Low-Temperature Thermoelectric Properties of β-Ag2Se Synthesized by Hydrothermal Reaction

“…3 Recently, several groups have reported wet chemical synthesis (including hydrothermal preparation) of the compound. [9][10][11][12] However, characterizations of TE properties, especially at low temperature, are relatively rare for b-Ag 2 Se samples prepared by chemical routes.…”