Pressure induced electronic and optical responses of vacancy-ordered double perovskites Cs 2 BX 6 (B = Zr, Pd, Sn; X = Cl, Br, I)

• Published in: Physica scripta 2023-11, Vol.98 (11), p.115520
• Main Authors: Hua, Howard (Jiaqi), Luo, Xuan
• Format: Article
• Language: English
• ISSN: 0031-8949; 1402-4896
• DOI: 10.1088/1402-4896/acff8f

Due to the toxicity and instability of lead-containing perovskites, high-performance lead-free perovskite attracts considerable attention. Lead-free vacancy-ordered double perovskites (VODP) emerge as environmentally friendly and efficient solutions as lead-containing solar cell substitutes. In this study, electronic properties of vacancy-ordered double perovskites Cs 2 BX 6 (B = Zr, Pd, Sn; X = Cl, Br, I) under high pressure are investigated using first-principles methods. Semiconductors with bandgaps between 1.1 to 1.6 eV are considered for application. Our results show Cs 2 PdCl 6 giving 1.60 and 1.32 eV bandgaps at 5 and 10 GPa, Cs 2 PdBr 6 yielding 1.22 eV at ambient pressure, Cs 2 SnBr 6 having 1.31 and 1.03 eV bandgap at 5 and 10 GPa, and Cs 2 ZrI 6 showing 1.52 and 1.28 eV bandgap at 15 and 20 GPa. Furthermore, we considered the absorption coefficient and spectrum to ensure the materials’ optical performance. Cs 2 PdCl 6 , Cs 2 PdBr 6 , and Cs 2 ZrI 6 display competent absorbance in the visible light range and proved these vacancy-ordered double perovskites as promising lead-free solar cell materials.