Cu-Embedded SnSe2 with a High Figure of Merit at Ecofriendly Temperature

Br doping-induced evolution of the electronic band structure in dimorphic and hexagonal SnSe2 thermoelectric materials

SnSe2 with its layered structure is a promising thermoelectric material with intrinsically low lattice thermal conductivity. However, its poor electronic transport properties have motivated extensive doping studies. Br doping effectively improves the power factor and converts the dimorphic SnSe2 to a fully hexagonal structure. To understand the mechanisms underlying the power factor improvement of Br-doped SnSe2, the electronic band parameters of Br-doped dimorphic and hexagonal SnSe2 should be evaluated separately. Using the single parabolic band model, we estimate the intrinsic mobility and effective mass of the Br-doped dimorphic and hexagonal SnSe2. While Br doping significantly improves the mobility of dimorphic SnSe2 (with the dominant hexagonal phase), it results in a combination of band convergence and band flattening in fully hexagonal SnSe2. Br-doped dimorphic SnSe2 is predicted to exhibit higher thermoelectric performance (zT ∼0.23 at 300 K) than Br-doped fully hexagonal SnSe2 (zT ∼0.19 at 300 K). Characterisation of the other, currently unidentified, structural phases of dimorphic SnSe2 will enable us to tailor the thermoelectric properties of Br-doped SnSe2.

Adsorption properties of small gas molecules on SnSe2 monolayer supported with transition metal: first-principles calculations

The adsorption properties of CH₄, H₂S, SO₂, CO, H₂O and NO molecules on transition metal-supported SnSe₂ surface are investigated by the first-principles method. The calculation results show that the transition metal (TM = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu) has the lowest adsorption energy when supporting at the Sn site of SnSe₂, indicating the system is relatively stable. Also, we find that CH₄, SO₂ and H₂O molecules tend to adsorb on Sc-supported SnSe₂ surface, H₂S and NO molecules prefer to adsorb on V-supported SnSe₂ surface, while CO molecule and Fe-supported SnSe₂ surfaces have strong interaction. And, CH₄, H₂S and H₂O molecules act as donors to provide electrons to the substrate, while SO₂, CO and NO molecules act as acceptors to gain electrons from the substrate. An analysis of charge difference density and density of states reveals that the adsorption energies of gas molecules are related to charge transfer and orbital hybridization. We hope that this work not only provides a promising sensor material, but also provides a new idea for the rational design of two-dimensional materials.

Tin-selenide as a futuristic material: properties and applications

SnSe/SnSe2 is a promising versatile material with applications in various fields like solar cells, photodetectors, memory devices, lithium and sodium-ion batteries, gas sensing, photocatalysis, supercapacitors, topological insulators, resistive switching devices due to its optimal band gap. In this review, all possible applications of SnSe/SnSe2 have been summarized. Some of the basic properties, as well as synthesis techniques have also been outlined. This review will help the researcher to understand the properties and possible applications of tin selenide-based materials. Thus, this will help in advancing the field of tin selenide-based materials for next generation technology.