Theoretical investigation of structural, electronic, and optical properties of halide cubic perovskite CsPbBr3-xIx

A comparative study of the mechanical stability, electronic, optical and photocatalytic properties of CsPbX3 (X = Cl, Br, I) by DFT calculations for optoelectronic applications

“…108 Thus, our ndings are in good agreement and very close to the other theoretical and experimental ndings. 32,82,103,[106][107][108]121,122 Importantly, we were able to tune the band gap of CsPbBr 3 to 2.061 eV, which is excellent suitable for optoelectronic and PV cell applications, whereas, our calculated E g value for CsPbI 3 was obtained to be 1.784 eV, which is in excellent agreement with the experimental value of 1.77 eV (ref. 119) and theoretical value of 1.73 eV (ref.…”

“…Young's modulus ( E ) is an indication of the degree of resistance offered by a material to longitudinal tension. 106 A comparative data set of E's ( Table 2 ) could be an inspiration for conducting further research on CsPbBr 3 for band gap tailoring and other purposes due to the comparatively high value of E . Pressure responses of CsPbX 3 are depicted in Fig.…”

“…From Table 1, it can be seen that aer several k-points tests the optimized lattice parameter a ¼ b ¼ c of CsPbCl 3 was 5.785 Å, which was elongated about 3.9% and 11.2% aer the replacement of halide Cl atom by Br and I atoms and the obtained values were in a great agreement with other theoretical and experimental values. 32,82,83,[102][103][104][105][106][107][108][109][110]123 From the cell parameters and volumes of CsPbX 3 (X¼ Cl, Br, I) results, a relation can be expressed as CsPbCl 3 < CsPbBr 3 < CsPbI 3 (Table 1) with volume increments of 12.4% and 37.8% for CsPbBr 3 and CsPbI 3, respectively.…”

“…Mechanical stability was justied under Born criteria for these crystals 111 and it is clearly seen that all are mechanically stable because they satisfy the condition C 11 + 2C 12 > 0, C 44 > 0 and C 11 À C 44 > 0 as well as another stability condition of C 12 < B < C 11 . 106 All of these in the bulk form are elastically anisotropic, conrmed by the relation 2C 44 ¼ C 11 À C 12 (ref. 112) and reconrmed by nonzero Zener's anisotropy factor A.…”

“…Young's modulus (E) is an indication of the degree of resistance offered by a material to longitudinal tension. 106 A comparative data set of E's (Table 2) could be an inspiration for 116 which is shown in Fig. 2(c).…”