Controllable Synthesis Of AgPb₁₀SbTe₁₂ Thermoelectric Materials By Solution Route And Their Comparable Transport Properties

AgPb_mSbTe_m+2 material is one of the most promising state-of-art thermoelectric materials, and it possesses relatively high thermoelectric properties. So far, the methods for the preparation of AgPb_mSbTe_m+2 materials have been mostly melt cooling method and mechanical alloying method, these two routes are readily to operate, yet high synthetic temperature is necessary and difficult to control the morphologies and sizes of the as-prepared samples. Since the sizes and morphologies have key influence in the thermoelectric properties of the materials, choosing appropriate synthetic route to prepare AgPb_mSbTe_m+2 with specific sizes and morphologies provides a new route for further improving thermoelectric properties.Here in this paper, mild hydrothermal and solvothermal method were chosen to prepare the products. AgPb₁₀SbTe₁₂ nanocubes and flower-like crystals having different sizes were obtained via adjusting experiment parameters (such as, the concentration of alkali, solvent, and surfactant et al.), and X-Ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Transmission Electron Microscopy (TEM), Energy Dispersive X-ray Spectroscopy (EDX), and thermoelectric integrated system test were used to systematically characterize the structure, morphology, composition, and thermoelectric properties of the samples, summarizing the relation among morphologies, structure, and properties.Experiment results indicate the as-synthesized AgPb₁₀SbTe₁₂ nanocubes and flower-like crystals with different sizes possess obvious size and shape dependent thermoelectric properties: AgPb₁₀SbTe₁₂ nanocubes present more excellent electrical conductivity compared to flower-like crystals, and the samples having smaller sizes have lower electrical conductivity for the products with the same morphologies; Moreover, the samples all go through the transformation from p-type semiconductor to n-type semiconductor; The thermal conductivities for the as-prepared products all decrease with rising temperature, and thermal conductivities are far more lower than the bulk materials.Based on the above synthesis route, amine-assisted solvothermal method was used to synthesize poly-crystalline AgPb₁₀SbTe₁₂ rods, and investigate the possible roles of different synthetic parameters (such as, acetone, synthetic temperature, formamide and hydrazine et al.) in the formation of AgPb₁₀SbTe₁₂ rods. A possible'in-situ self-sacrifice template'growth mechanism and chemical reaction mechanism is proposed integrating the experiment results.The transport property results of the AgPb₁₀SbTe₁₂ rods reveal the as-prepared samples display typical semiconductor character, the electrical conductivity increases with the rising temperature; and goes through the conversion from p-type semiconductor to n-type semiconductor like the naocubes and flower-like crystals.