First-Principles Investigation of Diverse Properties of X₂CaTa₂O₇ (X = Li, Na, K, and Rb) Ruddlesden–Popper Compounds for Photovoltaic Applications

Abstract

For the first time, we explored the optical, electronic, mechanical, and structural properties of the Ruddlesden–Popper phase family member X2CaTa2O7 (X = Li, Na, K, and Rb) by using density functional theory (DFT) with the Perdew–Burke–Ernzerhof (PBE) function in the generalized gradient approximation (GGA) framework. These materials show promising potential for energy conversion applications. Detailed investigations into structural parameters, band gaps, total and partial densities of states, and optical and mechanical properties demonstrate their suitability for photovoltaic technologies. The calculated electronic band gap structures and density of states demonstrate that X2CaTa2O7 (X = Li, Na, K, and Rb) are semiconductors in nature with band gaps ranging from 1.52 eV to 3.02 eV. Measurements demonstrate substantial contributions from O-2p4, Ca-4p4, and Ta-4f14 orbitals to the electronic structures of the compounds. Moreover, the optical characteristics, like the reflectivity, absorption coefficients (105 cm−1), dielectric functions (8.5), refractive index (2–3), and optical conductivity (4–6 fs−1), highlight the abilities of these compounds for optoelectronic and photovoltaic devices. Additionally, the mechanical properties measurements of the compounds show that they are capable for flexible electronic applications as well. This manuscript provides good insights into the design and development of the compounds capable for next-generation photovoltaic devices.

Keywords

• photovoltaic
• DFT
• density of states
• electronic band structure
• mechanical