Strong anharmonicity and high thermoelectric performance of cubic thallium-based fluoride perovskites TlXF₃ (X = Hg, Sn, Pb)

Abstract

State-of-the-art first-principles calculations are performed to investigate the thermoelectric transport properties in thallium-based fluoride perovskites TlXF3 (X = Hg, Sn, Pb) by considering anharmonic renormalization of phonon energy and capturing...

Structural, Electronic, Elastic, and Optical Properties of Cubic BaLiX₃ (X = F, Cl, Br, or I) Perovskites: An <i>Ab-initio</i> DFT Study

“…This is crucial as materials with flat band energy diagrams are highly likely to have strong anharmonicity and excellent thermoelectric properties [19][20]. Indeed, Song and coworkers [19] confirmed the flat band diagrams of some Thallium-based fluoro perovskites reported in our previous work [21]. They further confirmed that these types of perovskites have strong anharmonicity and high thermoelectric performance.…”

“…A literature study indicated that the abovementioned computational studies revealed that BaLiF 3 perovskite possesses quite a flat band diagram. This is crucial as materials with flat band energy diagrams are highly likely to have strong anharmonicity and excellent thermoelectric properties [19][20]. Indeed, Song and coworkers [19] confirmed the flat band diagrams of some Thallium-based fluoro perovskites reported in our previous work [21].…”

“…3 clearly illustrates that the materials have relatively flat band gaps, especially valence bands. This is a unique and interesting property that might lead to potential applications in other devices, including thermoelectric devices [19][20]. More importantly, the coexistence of the flat band gaps and the high dispersion in the band structure contributes to the immense power factor (PF), as the former provides a larger thermopower (S).…”

High thermoelectric performance in XAgSe2 (X = Sc, Y) from strong quartic anharmonicity and multi-valley band structure

“…The cumulative κ L as a function of the maximum average free path (MFP) indicates that the heat-carrying phonons have a considerably large MFP at 300 K. This implies that the κ L can be effectively reduced through nanostructuring. 43 For example, when the MFP is limited to 10 nm, the κ L of YAgSe 2 along the a ( b )-axis will be reduced by half. Additionally, the κ L of both materials exhibits weaker temperature dependence deviating from the universal law κ L ∼ T −1 , which is intimately related to the suppression of 3ph scattering phase space by quartic anharmonic renormalization.…”

Novel vacancy-ordered RbKGeCl6 and RbKGeBr6 double perovskites for optoelectronic and thermoelectric applications: an ab-initio DFT study

“…Similar trend was also observed for their vacancy ordered counterparts K 2 GeCl 6 and K 2 GeBr 6 [11] as well as Rb 2 GeCl 6 and Rb 2 GeBr 6 [13], where it was demonstrated that the anion substitution tunes the electronic band gap of the compounds. The progressive increase or decrease in the band gap energy as one of the cations of anions is substituted by an isoelectronic atom is characteristic feature observed across a wide range of perovskites [38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56]. This implies that cation and anion substitution is an effective way to tune the electronic properties of materials, which is very important to realize specific application in optoelectronic devices.…”