Investigation of near-room and high-temperature thermoelectric properties of (Bi0.98In0.02)2Se2.7Te0.3/Bi2Te3 composite system

Abstract

Polycrystalline composite samples of (Bi0.98In0.02)2Se2.7Te0.3/Bi2Te3 with different concentrations of Bi2Te3 such as 5%,10%,15% and 20% were prepared by the solid-state reaction technique. The X-Ray diffraction analysis has shown the hexagonal composite crystal structure with space group of $$R\overline{3 }$$ R 3 ¯ m. Field emission scanning electronic microscope shows secondary particles on the surface of the samples. All the samples have shown the usual semi-conducting behaviour throughout the temperature range. It is observed that bismuth has been co-ordinated with 6 selenium atoms in (Bi0.98In0,02)2Se2.7Te0.3 compound and it has enormous selenium vacancies. The electrical resistivity represents the noteworthy result of the grain boundaries leading to the higher content of scattering centres in the polycrystalline composite samples. It is found that the electronegativity differences of In and Te, In and Se are less than Bi and Se, Bi and Te is the reason for the decrease in Seebeck coefficient in the compound containing 15% and 20% of Bi2Te3.

Thermoelectric Composite of (Bi0.98In0.02)2Te2.7Se0.3/Bi2Se3 with Enhanced Thermopower and Reduced Electrical Resistivity

“…It was observed that anti-structure defects have a considerable impact on the carrier concentration in the current study's n-type (Bi 1−x In x ) 2 Te 2.7 Se 0.3 system. 16 Therefore, in continuation of the previous report, the structural, surface morphological, and thermoelectric characteristics of different composite material systems such as (Bi 0.98 In 0.02 ) 2 Te 2.7 Se 0.3 with varying concentrations of Bi 2 Se 3 (5%, 10%, 15%, and 20%) are examined in the high-temperature range of 30°C to 450°C.…”

Enhancing the thermoelectric properties for hot-isostatic-pressed Bi2Te3 nano-powder using graphite nanoparticles

“…To find the induced strain (ε) in the grain lattice, the Williamson-Hall (W-H) method [43] was employed. The FWHM of diffraction peaks and the grain size (D) are utilized in the commonly used W-H method in materials research to determine the strain value [27,44,45] according to Eq. ( 3).…”

“…Selenium (Se)-doped bismuth telluride (Bi 2 Te 2.7 Se 0.3 ) is n-type alloy which achieved a high ZT reaching a value of ~ 0.54 by reducing thermal conductivity and increasing electrical conductivity [4]. However, Pb, Sb, and Se are considered as toxic and not environmentally friendly elements [27][28][29].…”

Enhancement in thermoelectric performance of hydrothermally synthesized Ca and Sb co-doped Bi2Te3 nanostructures

“…Many synthesis techniques have been used in literature to increase the figure of merit (ZT) of a material. Various solution methods such as hydrothermal, solvothermal, co-prepetition, sol-gel, wet chemical, and refluxing are used for obtaining the nanostructures with different morphology and size [28][29][30][31][32]. To compete with the efficiency of traditional generators and refrigerators, the ZT value needs to be increased to ∼3 [33,34].…”