Sn-alloying of BaZrS3 chalcogenide perovskite as eco-friendly material for photovoltaics: First principle insight

This paper focuses mainly on investigating the effects of partial substitution of Zr cations by Sn cations on the structural, opto-electronic and photovoltaic properties of the chalcogenide perovskite BaZr1-xSnxS3 (x <= 0.25). For this purpose, we have used first-principles calculations. Through this approach, we show that the lattice constants and the gap energy (E-g) decrease as the Sn content (x) increases. Furthermore, the E-g values obtained decrease from 1.55 to 0.96 eV. our calculated decomposition energies suggest that it will be difficult to synthesize BaZr1-xSnxS3 alloys for higher Sn contents under thermal equilibrium conditions. Also, the calculated dielectric functions and absorption coefficient show a red shift for higher Sn content. Besides, our theoretical approach, indicate that, the compound BaZr0.815Sn0.125S3 presents a maximum photovoltaic efficiency eta of 32.5% for a thickness L = 500 nm, which is close to the Shockley-Queisser limit (33.7%), which makes it a promising candidate for the production of high power conversion efficiency solar cells with ultra-thin absorption layers. sulfide alloys for lead-free perovskite solar cells.