Pearl-necklace-shaped AgPb₁₀LaTe₁₂ microrods composed of self-assemble nanoparticles and their electrical transportation properties

Uniform and massive pearl-necklace-shaped AgPb₁₀LaTe₁₂ microrods covered by the thin amorphous PbO thin layers with the diameter of about 2 μm have been synthesized using citric acid (C₆H₈O₇) as a coordinating molecule. The as-obtained products were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM) and Raman spectroscopy techniques. It is found that the concentration of citric acid in the reaction mixture plays a vital role for controllable structures and morphologies. The morphology evolution of the particles has been traced as a function of reaction time and the ligand-driven irregular organization by citric acid coordinating uneven distribution metal ion of nanocrystals growth mechanism has been proposed to elucidate the formation of pearl-necklace-shaped AgPb₁₀LaTe₁₂ microrods. In addition, the electrical conductivities and Seebeck coefficients of the specimens were measured. The unusual electrical behaviors with temperature are attributed to charge carrier scattering at grain boundaries. The power factor of AgPb₁₀LaTe₁₂ microrods can reach about 240 μW·K^-2 m^-1 at 760 K.