Impact of pressure on perovskite MSnX3 (M = Li, Na; X = Cl, Br, I): A density functional theory study

In a significant stride towards sustainable energy solutions, a team of international researchers has uncovered the effects of pressure on the properties of tin-based halide perovskites, potentially revolutionizing the efficiency of solar cells. The study, led by Shuhua Yuan from the University of Electronic Science and Technology of China, provides a comprehensive analysis of the structural, electronic, and optical properties of MSnX₃ (M = Li, Na; X = Cl, Br, I) under varying pressure conditions.

The quest for renewable energy sources has led to a surge in research on perovskite solar cells, known for their exceptional advantages such as low manufacturing costs, high efficiency, and environmental friendliness. However, the stability and efficiency of these materials under different environmental conditions remain a challenge. This study focuses on tin-based halide perovskites, which are considered promising candidates for lead-free and flexible optoelectronics.

The researchers employed density functional theory (DFT) within the WIEN2k code and the full-potential linearized augmented-plane wave (FP-LAPW) approach to study the structural, electronic, and optical characteristics of MSnX₃ perovskites. They used the Perdew-Burke-Ernzerhof generalized gradient approximation (PBE-GGA) method for volume optimization and analyzed the materials in their cubic phase. The study investigated how changes in pressure affect the lattice constants, band gap nature, and optical absorption of these perovskites.

The findings reveal that the lattice constants of these compounds decrease with increasing pressure, with more significant changes observed when anions are substituted from Cl to I. Electronic analysis showed that these materials maintain their direct band gap nature under pressure, although the band gaps narrow with increasing pressure and larger anion sizes. Notably, Li/NaSnCl₃, Li/NaSnBr₃, and Li/NaSnI₃ may exhibit metallic behavior at pressures exceeding 5 GPa. Optical studies revealed significant pressure-induced enhancements in static dielectric constant and optical absorption, especially in the visible spectrum, highlighting the potential of these perovskites for solar cell applications.

This comprehensive analysis underscores the potential of these tin-based halide perovskites for advanced optoelectronic and photovoltaic technologies. The increase in the refractive index with pressure indicates a higher material density and enhanced optical performance, which is crucial for improving the efficiency of optoelectronic devices. The study provides valuable insights into how pressure can be used to fine-tune the properties of perovskite materials, offering a pathway to developing more efficient solar cells and other optoelectronic devices.

DOI: 10.1007/s11708-024-0970-4