Ab-initio investigation of the structural, electronic and optical properties of lead-free halide Cs2TiI6 double perovskites

DFT study of X‐site ion substitution doping of Cs 2 PtX 6 on its structural and electronic properties

“…For Cs 2 PtI y Cl 6− y , Cs 2 PtI y Br 6− y , and Cs 2 PtBr y Cl 6− y ( y = 0, 1, 2, 3, 4, 5, 6), the band structures are shown in Figure 4, Figures S1 and S2, respectively. It can be seen from the Cs 2 PtI y Cl 6− y , the indirect bandgap of Cs 2 PtI 6 was estimated to be 0.61 eV, which is in favorable agreement with the value reported in the Materials Projects and the literature using a similar computational approach 21 . In addition, we found that the type of bandgap of the Cs 2 PtBr y Cl 6− y and Cs 2 PtI y Cl 6− y changed from direct to indirect when y is from 0 to 1 in Figure 4 and Figure S2, and all the other perovskites have indirect band structure, conduction band minimum (CBM) and the valence band maximum (VBM) are at the X point and GAMMA point, respectively.…”

“…It can be seen from the Cs 2 PtI y Cl 6Ày , the indirect bandgap of Cs 2 PtI 6 was estimated to be 0.61 eV, which is in favorable agreement with the value reported in the Materials Projects and the literature using a similar computational approach. 21 In addition, we found that the type of bandgap of the Cs 2 PtBr y Cl 6Ày and Cs 2 PtI y Cl 6Ày changed from direct to indirect when y is from 0 to 1 in Figure 4 and Figure S2, and all the other perovskites have indirect band structure, conduction band minimum (CBM) and the valence band maximum (VBM) are at the X point and GAMMA point, respectively. This phenomenon indicated that the doping of a halogen will change the band structure type of Cs 2 PtCl 6 , but not destroy the main characteristics of the band structure of the other compounds.…”

“…Besides, the advantage that they can be simply prepared into thin films has also attracted the attention of scientists in the field of optoelectronics. Accordingly, calculating the physical properties of novel double perovskite will have a wide application prospect 21 . Bahmad et al studied the magnetic properties, magnetizations and magnetic susceptibilities, and phase diagrams of double perovskite Sr 2 VMoO 6 and Sr 2 RuHoO 6 using the Monte Carlo simulation 22,23 .…”

“…Accordingly, calculating the physical properties of novel double perovskite will have a wide application prospect. 21 Bahmad et al studied the magnetic properties, magnetizations and magnetic susceptibilities, and phase diagrams of double perovskite Sr 2 VMoO 6 and Sr 2 RuHoO 6 using the Monte Carlo simulation. 22,23 Mahmood et al studied the optoelectronics and thermoelectric applications of leadfree double perovskites halides Cs 2 TiCl 6 and Cs 2 TiBr 6 using density functional theory (DFT).…”

Titanium‐Based Vacancy‐Ordered Double Halide Family in Perovskite Solar Cells

“…Alternative compositional and structural derivatives of the perovskite family, specifically double halide perovskites (elpasolite) (general formula: A 2 B 1+ B 3+ X 6 ) [ 15 ] and vacancy‐ordered double halide perovskite (general formula: A 2 BX 6 ), [ 16 ] have been recently explored in overcoming the instability and toxicity issues of Pb‐based perovskites. [ 17 ] Double halide perovskites (DHPs) and vacancy‐ordered DHPs are a structural derivative of the archetypal perovskite structure (ABX 3 ). The structure is derived from conventional perovskites by doubling the ABX 3 unit cell along all three crystallographic axes and removing every other B‐site cation to form a face‐centered lattice of isolated BX 6 octahedral units bridged by A‐site cations in the void (vacancy‐ordered DHPs).…”