Synergistic manifestation of band and scattering engineering in the single aliovalent Sb alloyed anharmonic SnTe alloy in concurrence with rule of parsimony

Abstract

Several endeavors were adapted to improve the thermoelectric performance of SnTe as a substitute of toxic PbTe and booming approaches comprise introduction of nanostructuring, resonance states, valence band convergence and...

Ultralow Lattice Thermal Conductivity and Enhanced Mechanical Properties of Cu and Sb Co-Doped SnTe Thermoelectric Material with a Complex Microstructure Evolution

“…In the electronic structure of SnTe (Figure (a)), we can clearly see a band gap of 0.08 eV at the Γ point and an energy offset of 0.3 eV between the light hole valence band at the Γ point and heavy hole valence band at the Z + δ point in the Z → R direction in the Brillouin zone in agreement with the previous reports. , The band gap increases to 0.1 eV on doping of Cu in SnTe (Figure (b), Figure S4­(a)) similar to that in the case of dopants like Mg, Ca, and Cd. − Although the energy offset between the Γ point and Z + δ point remains unaltered, the bands appearing in the X → Γ region increase in energy, a feature not seen in the case of the above-mentioned dopants. This increase in the energy becomes significant in the case of Cu and Sb co-doped SnTe (Figure (c), Figure S4­(b)) with an energy offset of 0.24 eV between the M point and Γ point allowing participation of a greater number of valleys to transport. ,, The co-doped configuration also reveals band convergence with an energy gap of 0.22 eV between the Γ point and Z + δ point due to the synergistic interaction between Cu and Sb which leads to an increase in the Seebeck value due to the increase in the effective mass. ,, In addition, the p orbitals of Sb and Sn hybridize leading to increases in the densities of state (DOS) close to the Fermi level (Figure (d)). Such distortion in the DOS leads to improved Seebeck values at low temperatures as seen in the case of resonant dopants such as In, Bi, and Zn. ,,,, …”

“…17,22,40 The co-doped configuration also reveals band convergence with an energy gap of 0.22 eV between the Γ point and Z + δ point due to the synergistic interaction between Cu and Sb which leads to an increase in the Seebeck value due to the increase in the effective mass. 11,20,41 In addition, the p orbitals of Sb and Sn hybridize leading to increases in the densities of state (DOS) close to the Fermi level (Figure 2(d)). Such distortion in the DOS leads to improved Seebeck values at low temperatures as seen in the case of resonant dopants such as In, Bi, and Zn.…”

Gamma-irradiated stibnite thin films set a remarkable benchmark performance for photoelectrochemical water splitting

“…On the other hand, Sb photoelectron lines showed BE of 529.8 eV and 539.0 eV approving the presence of Sb 3d 5/2 and Sb 3d 3/2 states, respectively. The matching spin–orbit splitting of the Sb 3d photoelectron line is about 9.2 eV, while the two relative line intensities in the doublet are Sb 3pd 5/2 : Sb 3p 3/2 = 3 : 2, which suggests the existence of Sb 3+ valence states, 39 as shown in Fig. 4b .…”

Pushing the limit of synergy in SnTe-based thermoelectric materials leading to an ultra-low lattice thermal conductivity and enhanced ZT

“…To enhance the power factor, electronic band engineering through strategies such as band convergence, resonant doping, energy ltering, and a synergistic combination of the above methods has proven to be the ultimate go-to strategies. 17,18,[27][28][29][30][31][32][33] Defect engineering through microstructure scale control, lattice strains, interface engineering, and so phonon modes, among others, have been shown to effectively scatter phonons leading to low thermal conductivity values. 20,[34][35][36][37][38][39][40] Most recently, the possibility of n-type SnTe has been reported, thus enhancing the possibility of fabrication of a homogeneous thermoelectric device.…”