Study of lead-free vacancy ordered double perovskites Cs₂TeX₆ (X = Cl, Br, I) for solar cells, and renewable energy

Abstract

Herein, the electronic, optical, mechanical, and transport properties of a double perovskites Cs2TeX6 (X = Cl, Br, I) are explored with the focus on solar cell and thermoelectric applications by the density functional theory (DFT). The feasibility of structural, thermodynamic, and elastic stabilities is arbitrated by a tolerance factor, formation energy, and elastic constant, respectively. Further, the Poisson and Pugh’s ratio display the ductile behavior of studied compounds. From the electronic properties analysis, it is revealed that the bandgap decreases by changing Cl with Br, and I from 2.67 eV to 2.52 eV and 1.73 eV, respectively which in results tune the optical properties from visible to infrared region. The shifting of maximum absorption from visible to infrared region makes them promising materials for solar cell and remote sensing devices. Moreover, various optical parameters including refractive index, reflectivity, and optical loss were also reported. Additionally, the transport characteristics were analyzed by electrical, thermal conductivities, and figure of merit (ZT) versus temperature and chemical potential effect. The ZT increases from Cl to I substitution. At the end, the thermodynamic behavior studied by specific heat capacity, Debye temperature and Hall coefficient was presented. All these characteristics have demonstrated that our studied materials are excellent choice for probing solar cell and renewable energy applications.

Lead-free Perovskites TlGeClxBr3-x (x=0,1,2,3) as Promising Materials for Solar Cell Application: a DFT Study

“…This is generally true for a large range of ABX3 perovskite compounds, where X anions are replaced by their counterparts with larger ionic radii [67][68][69][70][71][72]. This is also observed for double perovskites [73][74][75][76][77][78][79][80][81][82][83][84][85][86][87][88][89][90][91][92]. The optimized lattice constants of TlGeCl3, TlGeCl2Br, TlGeClBr2, and TlG perovskites are 5.244 Å, 5.336 Å, 5.416 Å, and 5.501 Å, respectively (Table 1).…”

First principle studies on structural, elastic, electronic, optical, and thermoelectric properties of new perovskite TlTaO3: For renewable energy applications

“…Despite the fact that several oxide‐based perovskites (ABO 3 ) have been reported recently, a few novel perovskite compounds (ABO 3 ), in which A and B belong to the alkali and alkaline earth elements and O belongs to oxygen having highest electronegativity 3,10–12 . When combined with alkaline earth metals and low electro‐negative alkali metals, oxygen has the capacity to generate compounds with high structural stability, which possess outstanding electronic properties, such as the band gap ranges widely from semiconductors to insulators 13–19 . Significant uses for these substances include the production of extremely effective solar materials, electronics, and lenses.…”

DFT study of the half‐metallic variant perovskites A2OsX6 (A = Rb/Cs; X = Cl/Br) for spintronic and thermoelectric applications

“…These compounds crystallize in the Fm$$$ \overline{3} $$$m cubic structure with space group 225 (Figure 1). A variety of the vacancy ordered double perovskites have recently been studied with prospects in spintronics, optoelectronics, and thermoelectric power generation [15–21].…”