Phase-Transition-Dependent Conductivity and Thermoelectric Property of Silver Telluride Nanowires

Abstract

Silver telluride nanowires have been synthesized by the composite-hydroxide-mediated (CHM) method at temperatures of 180−225 °C. The products were single-crystalline nanowires and monoclinic phase Ag2Te with a high purity. The reversible structural phase transition from monoclinic structure (β-Ag2Te) to face-centered cubic structure (α-Ag2Te) around 148/133 °C was observed during the heating/cooling process. The latent heat of the phase transition was calculated. The electrical resistance and thermal emf versus temperature were for the first time investigated on the Ag2Te nanowires. Abrupt changes of conductivity and Seebeck coefficient around the phase transition temperature were observed. The maximum Seebeck coefficient is ∼170 and ∼160 μV K−1 during the heating and cooling process, respectively, indicating a promising one-dimensional thermoelectric material as a building block to construct nanodevices.

Room-Temperature Chemical Synthesis of Silver Telluride Nanowires

“…10 On heating, resistance decreases with increase in temperature in the monoclinic phase, and subsequently, upon increasing the temperature further, it increases with the nucleation of the cubic phase. 9,10 An abrupt increase in resistance was observed as the monoclinic phase changes to the cubic phase. 15 During cooling, a similar trend was observed, but the temperature of the phase change was different from that on heating.…”

“…3 Silver chalcogenides, particularly Ag 2 Te, have been receiving tremendous attention due to their interesting semiconducting properties. [4][5][6][7] In addition, Ag 2 Te is known to show a phase transition from the low-temperature monoclinic phase ( -Ag 2 Te) to the hightemperature face-centered cubic phase (R-Ag 2 Te) at ∼423 K. [8][9][10] Low-temperature -Ag 2 Te is a narrow band gap semiconductor with high electron mobility and low lattice thermal conductivity. 11 In the R-Ag 2 Te phase, silver cations can move freely, which enhances the conductivity, leading to superionic conductivity.…”

“…18,15 Recently, Li et al found a maximum Seebeck coefficient of -170 µV K -1 for 1D Ag 2 Te NWs. 9 Magnetic field dependent magnetothermopower was found in p-type Ag 2-δ Te, which shows a maximum value at 7 T. 19 The ability of nanomaterials to exhibit an enhanced thermoelectric effect is thought to be very significant toward the development of highefficiency devices and sensors. 21 and the sonication of Te and silver acetate in ethylene glycol.…”

“…11 Recently, Ag 2 Te NWs were synthesized by a composite-hydroxide-mediated (CHM) method, where AgNO 3 and Te powder were heated at 498 K in a Teflon vessel containing ethylenediamine and hydrazine hydrate. 9 The synthesis of Ag 2 Te nanorods in a reaction of Te nanorods and AgNO 3 in hydrazine and Na 2 EDTA at 333 K has been reported. 24 In this report, we demonstrate a room-temperature solution-phase route for the synthesis of Ag 2 Te NWs by the direct reaction of Te NWs with AgNO 3 .…”

Low temperature reduction route to synthesise bismuth telluride (Bi2Te3) nanoparticles: structural and optical studies

“…During the past decade, low-cost and less hazardous direct wetchemical route has been used to synthesise some nanostructures, such as films, nanorods, nanowires and nanobelts of oxides, metals, semimetal, alloys and other compounds [22][23][24][25]. Furthermore, the two-step Te template-directed synthesis is one of the most popular strategies for the fabrication of telluride nanostructures and uses N 2 H 4 .H 2 O as a common reducing agent [26][27][28][29][30][31][32][33][34].…”