Organic ligand displacement by metal salts to enhance nanoparticle functionality: thermoelectric properties of Ag2Te

Facile Surfactant‐Free Synthesis of p‐Type SnSe Nanoplates with Exceptional Thermoelectric Power Factors

“…S for 1 increases almost linearly with temperature (250 mVK À1 at room temperature to 340 mVK À1 at 550 K). By comparison, 2 shows n-type behavior at room temperature (S % À150 mVK À1 ), with the value of S becoming positive (p-type behaviour) at % 490 Kand rising to % 80 mVK À1 at 550 K. It is possible that the n-type conducting behavior correlates to the presence of Cl and/or aslight excess of Sn, as noted above.We are currently investigating this behavior further in systematic doping experiments.A nn /p or p/n inversion with increasing temperature has also been observed in pellets consolidated from PbTe, Ag 2 Te,a nd PbTe 0.1 Se 0.4 S 0.5 synthesized through surfactant-assisted solution methods, [7,15] and should be related to the thermal activation of higher concentrations of positive or negative charge carriers,r espectively. [7b] It is also notable that both s and S increase with temperature for 1.…”

“…[6] However,the organic surfactants that can control morphology through surface modification are commonly electrically insulating, which can drastically reduce the electrical conductivity of the materials. [7] Ligand replacement methods switch smaller species for long chain surfactant molecules, [7] but sometimes involve using high toxicity chemicals, [8] and introduce impurities, [7b] which again can adversely influence the transport behavior of the materials. [7b] Organic contamination can be prevented only if as uitable surfactant-free synthesis strategy can be found, [9] and to date solution syntheses of SnSe nanostructures have required organic surfactants and/or solvents,f or example,o leyamine, trioctylphosphine selenide,a nd bis[bis(trimethylsilyl) amino]tin(II), while only yielding milligram quantities of materials.…”

Composition Modulation of Ag2Te Nanowires for Tunable Electrical and Thermal Properties

“…The same treatment for C p has been reported in several papers on Ag 2 Te. [5][6][7] Modeling with Boltzmann Transport Equations. We also model the charge carrier transport for the materials in ambipolar transport regime using the near-equilibrium Boltzmann transport equations under the relaxation time approximation.…”

Synthesis and Thermoelectric Properties of Noble Metal Ternary Chalcogenide Systems of Ag–Au–Se in the Forms of Alloyed Nanoparticles and Colloidal Nanoheterostructures

“…43,44 Binary silver chalcogenides have also been tested as thermoelectric materials, showing values of the thermoelectric figure of merit (ZT) close to unity in some cases. [45][46][47][48][49] In the context of thermoelectrics, Xiao et al have reported higher ZT values for ternary Ag 4 SeS alloyed NPs, compared to the binary Ag 2 Se NPs. 50 Other materials in the research spotlight are CuAgSe, AgSbSe 2 and AgBiSe 2 systems, which are currently emerging as promising thermoelectric materials with enhanced ionic and electronic mobilities and ultra-low thermal conductivities.…”