Structural, Electronic, and Optical Properties of CsPb(Br1-xClx)3 Perovskite: First-Principles Study with PBE-GGA and mBJ-GGA Methods.

Hamid M Ghaithan,Zeyad A Alahmed,Abdullah S Aldwayyan,Saif M H Qaid

doi:10.3390/ma13214944

Abstract

The effect of halide composition on the structural, electronic, and optical properties of CsPb(Br1−xClx)3 perovskite was investigated in this study. When the chloride (Cl) content of x was increased, the unit cell volume decreased with a linear function. Theoretical X-ray diffraction analyses showed that the peak (at 2θ = 30.4°) shifts to a larger angle (at 2θ = 31.9°) when the average fraction of the incorporated Cl increased. The energy bandgap (Eg) was observed to increase with the increase in Cl concentration. For x = 0.00, 0.25, 0.33, 0.50, 0.66, 0.75, and 1.00, the Eg values calculated using the Perdew–Burke–Ernzerhof potential were between 1.53 and 1.93 eV, while those calculated using the modified Becke−Johnson generalized gradient approximation (mBJ–GGA) potential were between 2.23 and 2.90 eV. The Eg calculated using the mBJ–GGA method best matched the experimental values reported. The effective masses decreased with a concentration increase of Cl to 0.33 and then increased with a further increase in the concentration of Cl. Calculated photoabsorption coefficients show a blue shift of absorption at higher Cl content. The calculations indicate that CsPb(Br1−xClx)3 perovskite could be used in optical and optoelectronic devices by partly replacing bromide with chloride.

Highlights

The RMT * kmax value was set at 9.0 (RMT is the smallest muffin-tin radius in the unit cell and kmax is the maximum value of the reciprocal lattice vectors)
The irreducible Brillouin zone (IBZ) was produced using 500 k-points (12 × 12 × 3 mesh grids) and the self-consistent convergence of total energy was set at 10−4 Ry
* Koller, Tran, and Blaha modified Becke-Johnson potential; ** Gritsenko, van Leeuwen, van Lenthe, and Baerends-Solid and Correlation; *** Quantum Espresso 6.0; **** Hybrid nonlocal exchange-correlation functional. These results indicate the bowing parameters b = 0.25154, 0.23037, −0.14156, and − 0.14902 eV for the energy band gap (Eg) obtained using Perdew–Burke–Ernzerhof generalized gradient approximation (PBE–GGA), modified Becke−Johnson generalized gradient approximation (mBJ–GGA), mBJ–GGA + spin-orbital coupling (SOC), and mBJ–GGA + SOC(C), respectively

Summary

Introduction

Organic and inorganic perovskites have gained considerable attention in the field of optoelectronics, and more recently in solar cells [1,2,3,4,5,6,7,8] and light-emitting devices [9,10,11,12,13], thanks to the reduced costs [14], high quantum efficiency of photoluminescence [15], and extensively tunable emission wavelengths of these materials [16,17,18]. Structural distortion occurs and the structure of CsPbBr3 is converted to tetragonal (88 ◦ C < T < 130 ◦ C), and subsequently to cubic at higher temperatures (T > 130 ◦ C) [17,18,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38]. Structural distortion occurs and the CsPbCl3 structure is converted to tetragonal (42 ◦ C < T < 47 ◦ C), and subsequently to cubic at higher temperatures (T > 47 ◦ C) [18,39]. The energy band gap (Eg ) can be adjusted by adding

Methods

Results

Conclusion