Isovalent substitution in metal chalcogenide materials for improving thermoelectric power generation – A critical review

Abstract

The adverse effect of fossil fuels on the environment is driving research to explore alternative energy sources. Research studies have demonstrated that renewables can offer a promising strategy to curb the problem, among which thermoelectric technology stands tall. However, the challenge with thermoelectric materials comes from the conflicting property of the Seebeck coefficient and the electrical conductivity resulting in a low power factor and hence a lower figure of merit. Researchers have reported various techniques to enhance the figure of merit, particularly in metal chalcogenide thermoelectric materials.Here we present a review on isovalent substitution as a tool to decouple the interdependency of the electrical conductivity and Seebeck coefficient to facilitate simultaneous enhancement in these two parameters. This is proven true in both cationic and anionic side substitutions in metal chalcogenide thermoelectric materials. Numerous publications relating to isovalent substitution in metal chalcogenide thermoelectric are reviewed. This will serve as a direction for current and future research to enhance thermoelectric performance and device application. This review substantiates the role of isovalent substitution in enhancing metal chalcogenide thermoelectric properties compared with conventional systems.

Rb2CdSi4S10: novel [Si4S10] T2-supertetrahedra-contained infrared nonlinear optical material with large band gap

“…[33][34][35][36][37] Whereas to create a large SHG response in sulfide, the [MS 4 ] (M = d 10 metals, IIIA, IVA and VA group elements) tetrahedra with strong covalent bonds could be used as the NLO-active units. [38][39][40][41] In addition, to achieve the desired balance between the wide E g and the large SHG response, the atomic coordination of AAEMs, unit-arrangement and the density of the NLO units should be carefully designed. 42 Recently, by grouping AAEMs and [Ga 4 S 10 ] T2-ST with or without electronegative halogens, several gallium sulfides with large E g s, such as [ABa 3 Cl 2 ][Ga 5 S 10 ] (A = K, Rb, Cs), 43 S1, ESI †), indicating that the [Si 4 S 10 ] T2-ST could also be a good NLO-active unit for the design of new IR-NLO materials with a large E g .…”

Multidiscipline Applications of Triboelectric Nanogenerators for the Intelligent Era of Internet of Things

“…Compared with common energy-harvesting and energy storage devices (e.g., supercapacitors, lithium-ion, batteries, solar cells, and thermoelectric cells [194][195][196][197][198][199]), the output characteristics of TENGs in high-voltage and low-current characteristics lead to an impedance mismatch between TENG and the power management circuit. Therefore, the transformers are often used to regulate the output performance and impedance of TENGs.…”

Enhanced Thermoelectric Properties of Zr0.85–xHfxNb0.15–yTayCoSb Medium-Entropy Alloys: Tradeoff between “What to Alloy” and “How Much to Alloy”

“…Thermoelectricity is a green energy-conversion technology that has attracted increasing levels of interest in recent decades, in which waste heat is directly and efficiently converted into electricity . Thermoelectric (TE) efficiency is determined by the dimensionless figure of merit (ZT = S 2 σ T /κ, where T is the absolute temperature, S is the Seebeck coefficient, σ is the electrical conductivity, and κ is the total thermal conductivity) . Several strategies have been developed in recent years to improve the ZTs of TE materials, including band engineering, , phonon engineering, − the use of energy-filter effects, , grain boundary engineering, , texture engineering, and entropy engineering, − among others.…”