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One of the hot materials in thermoelectric is the skutterudite CoSb3 compound, which shows excellent potential as a thermoelectric material because Sb-based skutterudite thermoelectric materials have high mobility, large atomic mass, and high electrical conductivity. The effort of substituting transition metal (Fe) or (Ni) ions at Co site is an attempt to modify the local distortion and increasing electrical conductivity. In this work, we report the synthesis of the skutterudite CoSb3 compound using a modified polyol method. We used CoCl2.6H2O, FeCl3.6H2O, NiCl2, and SbCl3 raw materials as precursors. During the process, we used polyvinylpyrrolidone (PVP) as a stabilizer. The precursors were reduced by NaBH4 in tetraethylene glycol (TEG) at 513 K in a nitrogen atmosphere with 30 minutes for holding times. The yielded products were characterized by XRD, SEM-EDX, FTIR, and electrical conductivity. From the analysis of XRD data, we found that the nanoparticles show grain size between 15 to 32 nm. The nanoparticles were mostly identified as the CoSb3 phase, and the other phase of CoSb2 was also detected. And then, from the analysis of SEM-EDX data, there was agglomeration in the samples so that the particles size become larger and unstable. The chemical bonds of samples actually in the wavenumber range below 500 cm-1. The electrical conductivity increased with increasing stoichiometry fractions of Co1-xFexSb3 (x = 0, 0.05, and 0.1) or Co1-xNixSb3 (x = 0, 0.15, and 0.2) indicating that the samples can be used as a raw material for the thermoelectric device. The values of electrical conductivity for samples lay between 103 to 104 Ω-1cm-1, which also indicates the samples were semiconductors. [ABSTRACT FROM AUTHOR]

Energy demand is increasing significantly, while conventional energy resources. Carried out by developing and exploring materials which are potentially applied as an alternative renewable energy device. Nowadays, the utilization of thermal energy attracts the research interest due to its abundant quantities. Thus, thermoelectric as a thermal conversion device into electrical energy is the best alternative for confronting this matter. Thermoelectric studies continue to be encouraged, one of them is SrTiO3 based material. For investigating the scientific information and its application, a comprehensive study was needed by modifying the local structure using Bi dopant on SrTi1-xBixO3 system. SrTi1-xBixO3 was prepared via solid-state reaction followed by calcination, molding process, and sintering at 860 °C. In this work, the various molar ratio of Bi doping was performed. Substitution of Bi in Ti position of SrTiO3 was intended to find its potential as a high-temperature thermoelectric material. XRD identified cubic crystal structure of SrTi1-xBixO3 with a space group of P m -3 m. Cell dimensions different for all fractions, the biggest one was performed by x = 0.10. Electrical conductivity of samples induced by thermal condition relatively increase as the fractions larger. The linear fit of UV-Vis Spectrophotometer data confirmed that SrTi1-xBixO3 was classified as semiconductor material with a wide bandgap which is potentially applied for the thermoelectric device. [ABSTRACT FROM AUTHOR]