A theoretical study of the structural, thermoelectric, and spin‐orbit coupling influenced optoelectronic properties of CsTmCl₃ halide perovskite

Abstract

This first principles study explores the structural, electronic, optical, and thermoelectric properties of the CsTmCl3 halide perovskite using density functional theory. The structural and thermoelectric properties are calculated without considering the spin‐orbit coupling (SOC), while both the electronic and optical properties are calculated with and without the SOC effect. A comparison of the results obtained with and without SOC reveals that inclusion of the SOC effect reduces the band gap from 1.18 to 0.99 eV due to shifting of the Tm‐d states toward the Fermi level. However, direct nature of the band gap remains the same in both the cases. The effect of SOC on the optical properties is, however, only visible in shifting of the third characteristic peak to lower energies. Strong optical absorption in the visible and ultraviolet regions shows effectiveness of CsTmCl3 in the optical devices working in these regions. Moreover, the calculated transport properties reveal CsTmCl3 as a useful thermoelectric material at room temperature.

Metal Halide Perovskites as Emerging Thermoelectric Materials

“…Recently, high Seebeck coefficients − and higher stability , have been anticipated for the newly emerging double perovskites, including Cs 2 AgBiX 6 (X = Cl, Br), CsInAgX 6 , Cs 2 PbX 6 (X = Cl, Br, I), Cs 2 GeMnX 6 (X = Cl, Br), Cs 2 GeNiX 6 (X= Cl, Br), A 2 AgTlCl 6 (A = Rb, Cs), and Cs 2 BCl 6 (B = Se, Te) . Some other lead-free MHPs were also predicted to have promising TE properties, such as CsTmCl 3 , as well as the chalcogenide perovskite-like analogue BaZrS 3 . Furthermore, low-dimensional quasi-2D RP perovskites may be promising for TE applications due to the potential for high power factors as well as their exceptionally low thermal conductivity. , These perovskites can be viewed as natural superlattices, while it is well known that superlattices may yield an improved TE performance. , Nanostructuring is yet another well-known approach for the enhancement of TE performance in general, but studies of the TE properties of MHP nanostructures have been scarce so far.…”

Probing the physical properties of M2LiCeF6 (M = Rb and Cs) double perovskite compounds for prospective high-energy applications employing the DFT framework

“…Thus, the TB-mBJ approximation was successfully used in some recent studies to correct the underestimated troublesome band gaps. [46][47][48][49] The optimal geometries of the M 2 LiCeF 6 (M = Rb and Cs) compounds with assessed energy band structures over larger symmetries are displayed in Fig. 3a and b, respectively.…”

First‐principles investigation of structural, electronic, and optical properties of transition metal‐dopedC40 CrSi2

“…It is well known that the electronic properties of a solid or compound are related to the electronic interactions between atoms and the atoms near the Fermi level (E F ). [68][69][70][71] To study the influence of TMs on the electronic properties of C40 CrSi 2 silicide, Figure 3 shows the calculated band structure of the C40 CrSi 2 and TM-doped C40 CrSi 2 silicide along the Brillouin zone in a high symmetrical direction. In this paper, it can be seen that the calculated indirect energy band of the parent C40 CrSi 2 silicide is 0.391 eV, which is in good agreement with the other theoretical results (0.3-0.35 eV).…”