Surfactant-Free Synthesis of Bi₂Te₃−Te Micro−Nano Heterostructure with Enhanced Thermoelectric Figure of Merit

Abstract

The calculation of lattice contribution in thermal conductivity:According to Wiedemann-Franz law (Equation S1), the thermal conductivity can be split into two parts: the lattice part (к L ) and electron part (к e ). к e is the product of the Lorentz number (L) with electrical conductivity and temperature. For heavily degenerated semiconductors (including our materials), 2.0 × 10 -8 V 2 K -2 is accepted as the appropriate value of the Lorentz number L. К = К L +К e = К L + LσT (S1) Due to the anisotropic properties of bismuth telluride, in this work we tested the in-plane charge transport properties and cross-plane thermal transport properties. Z. Ren and co-workers have done a very detailed study on the anisotropic TE properties of Bi 2 Te 2.7 Se 0.3 . 1 In-plane conductivity (perpendicular to press direction) is reported to be higher for both electrical and thermal test than cross-plane (parallel to press direction) by about 10%-20%. Therefore, in this work, we applied a modified factor ~0.8 to estimate the cross-plane electrical conductivity from the experimental in-plane electrical conductivity, resulting in the modification of Equation S1 to Equation S2.Here, К , К L and К e are thermal conductivities of the total, lattice part and electron part in the cross-plane orientation respectively; and σ is the electrical conductivity in the in-plane

Synthesis and Thermoelectric Properties of Copper Sulfides via Solution Phase Methods and Spark Plasma Sintering

“…The energy crisis and environmental problems have promoted the swift development of TE materials in the past few decades [1][2][3][4]. Compared to the mainstream tellurium-based TE materials [5][6][7][8], nanostructured metal chalcogenides with low cost, low toxicity, and abundant elements exhibit interesting physical properties [9,10]. Therefore, nanostructured metal chalcogenides TE materials such as Cu-Se [11][12][13] and Cu-S materials [14][15][16][17] have received more attention.…”

Heterojunction double dumb-bell Ag2Te–Te–Ag2Te nanowires

“…1,2 These properties open up new avenues for the application of hybrid nanomaterials in various fields such as thermoelectrics, [3][4][5][6] photocatalysis, 7-10 battery applications, 11 sensors, 12 data storage, 13 etc. Interest in one dimensional (1D) nanostructures has grown considerably over the years as they act as better model systems for studying nanoscale structure-property correlations and effects of quantum confinement.…”

Chemical Trends of Electronic Properties of Two-Dimensional Halide Perovskites and Their Potential Applications for Electronics and Optoelectronics

“…One is to enhance the Seebeck coefficient or the PF using band structure engineering methods, [5] such as modifying the electronic density of states and Fermi energy through doping heteroatoms, reducing crystal symmetry to achieve high band edge degeneracy, [6][7][8] etc. The other is to reduce thermal conductivity using methods such as nanostructuring, [9][10][11][12][13][14][15][16][17][18][19][20][21] alloying, [14,[22][23][24][25][26] etc. These strategies have achieved significant progress in the past decade.…”