The ACdX3 (A = Li, Na, K, Rb, Cs, Fr; X = Cl, Br) perovskite family has attracted interest due to its promising properties for solar applications. This study employs DFT calculations to analyze their thermodynamic, structural, electronic, optical, mechanical, and phonon properties, alongside population analysis. The formation enthalpy values are negative for all materials, indicating that they are thermodynamically stable. Among them, CsCdCl3 is the most thermodynamically stable. Tolerance factor calculations suggest that compounds from KCdCl3 to FrCdBr3 are structurally stable, whereas the others are not. Bandgap evaluations using GGA-PBE and m-GGA reveal a downward trend as the A-site cation size increases, decreasing from 1.854 eV (LiCdCl3) to 1.674 eV (FrCdCl3) and 0.797 eV (LiCdBr3) to 0.634 eV (FrCdBr3), reinforcing their semiconducting behavior. Further insights are provided by PDOS and DOS analyses. Optical studies demonstrate a peak absorption coefficient of 2.5 × 105 cm⁻1 in the 13–15 eV range for CsCdCl3, with all materials exhibiting moderate to strong absorption in the 1.5–4 eV range, suggesting their potential for solar cell applications. The combination of high optical conductivity, strong dielectric constants, and low reflectance further emphasizes their suitability for optoelectronic applications. Mechanical analysis verifies that all materials satisfy the born stability criteria, confirming their mechanical stability. These compounds exhibit ductile behavior, with Pugh’s ratios exceeding 1.75 and Poisson’s ratios between 0.27 and 0.34. Anisotropy values below unity indicate directional shear resistance. Additionally, shear modulus, Young’s modulus, and bulk modulus were evaluated. Phonon dispersion analyses reveal dynamical instabilities in LiCdCl3, LiCdBr3, NaCdCl3, NaCdBr3, KCdCl3, KCdBr3, RbCdCl3, RbCdBr3, CsCdBr3, FrCdCl3, and FrCdBr3, as indicated by the presence of imaginary phonon frequencies. In contrast, CsCdCl3 exhibits no imaginary modes, suggesting dynamical stability. Population analysis further explores bonding characteristics. In summary, CsCdCl3 emerges as the most promising material, offering superior optical absorption, structural stability, and mechanical resilience, positioning ACdX3 perovskites as lead-free, sustainable materials for future energy applications.

Exploring ACdX₃ Perovskites: DFT Analysis of Stability, Electronic, Optical, and Mechanical Properties for Solar Applications

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发表日期：

2025年5月10日

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Imtiaz Ahamed Apon,
Siam Jubayer,
Rabah Boudissa,
Riyad Kawsar,
Rifat Rafiu,
Moamen S. Refat,
Md. Sakib Hasan Saikot,
Amnah Mohammed Alsuhaibani,
Md. Azizur Rahman,
Md. Alamgir Hossain,
Noureddine Elboughdiri

摘要

The ACdX₃ (A = Li, Na, K, Rb, Cs, Fr; X = Cl, Br) perovskite family has attracted interest due to its promising properties for solar applications. This study employs DFT calculations to analyze their thermodynamic, structural, electronic, optical, mechanical, and phonon properties, alongside population analysis. The formation enthalpy values are negative for all materials, indicating that they are thermodynamically stable. Among them, CsCdCl₃ is the most thermodynamically stable. Tolerance factor calculations suggest that compounds from KCdCl₃ to FrCdBr₃ are structurally stable, whereas the others are not. Bandgap evaluations using GGA-PBE and m-GGA reveal a downward trend as the A-site cation size increases, decreasing from 1.854 eV (LiCdCl₃) to 1.674 eV (FrCdCl₃) and 0.797 eV (LiCdBr₃) to 0.634 eV (FrCdBr₃), reinforcing their semiconducting behavior. Further insights are provided by PDOS and DOS analyses. Optical studies demonstrate a peak absorption coefficient of 2.5 × 10⁵ cm⁻¹ in the 13–15 eV range for CsCdCl₃, with all materials exhibiting moderate to strong absorption in the 1.5–4 eV range, suggesting their potential for solar cell applications. The combination of high optical conductivity, strong dielectric constants, and low reflectance further emphasizes their suitability for optoelectronic applications. Mechanical analysis verifies that all materials satisfy the born stability criteria, confirming their mechanical stability. These compounds exhibit ductile behavior, with Pugh’s ratios exceeding 1.75 and Poisson’s ratios between 0.27 and 0.34. Anisotropy values below unity indicate directional shear resistance. Additionally, shear modulus, Young’s modulus, and bulk modulus were evaluated. Phonon dispersion analyses reveal dynamical instabilities in LiCdCl₃, LiCdBr₃, NaCdCl₃, NaCdBr₃, KCdCl₃, KCdBr₃, RbCdCl₃, RbCdBr₃, CsCdBr₃, FrCdCl₃, and FrCdBr₃, as indicated by the presence of imaginary phonon frequencies. In contrast, CsCdCl₃ exhibits no imaginary modes, suggesting dynamical stability. Population analysis further explores bonding characteristics. In summary, CsCdCl₃ emerges as the most promising material, offering superior optical absorption, structural stability, and mechanical resilience, positioning ACdX₃ perovskites as lead-free, sustainable materials for future energy applications.

Exploring ACdX3 Perovskites: DFT Analysis of Stability, Electronic, Optical, and Mechanical Properties for Solar Applications

摘要

Exploring ACdX₃ Perovskites: DFT Analysis of Stability, Electronic, Optical, and Mechanical Properties for Solar Applications