Suppressed Defects and Improved Stability of All-Inorganic CsSnI₃ Films by Solid Additive-Assisted Chemical Vapor...

Area of Science:

• Materials Science
• Renewable Energy
• Solid-State Chemistry

Background:

• All-inorganic tin-based halide perovskite CsSnI₃ offers a lower toxicity and narrower bandgap alternative to lead-based perovskites for solar cells.
• CsSnI₃ suffers from rapid degradation in air and intrinsic defect states, hindering its optoelectronic and device performance.

Purpose of the Study:

• To develop a method for preparing high-quality CsSnI₃ films with enhanced stability.
• To elucidate the mechanism behind improved film properties using theoretical and experimental techniques.

Main Methods:

• Solid additive-assisted chemical vapor deposition (SACVD) was employed to synthesize CsSnI₃ films.
• Theoretical calculations, Fourier transform infrared spectroscopy, temperature-dependent photoluminescence, and scanning Kelvin probe techniques were utilized for characterization.

Main Results:

• The SACVD method successfully produced high-quality CsSnI₃ films.
• Coordination interactions between the solid additive's lone electron pairs and Sn²⁺ were confirmed, suppressing Sn²⁺ oxidation to Sn⁴⁺.
• A significant reduction in defect density was observed, leading to improved film properties.

Conclusions:

• The study presents a novel strategy for fabricating stable, eco-friendly tin halide perovskite thin films for perovskite solar cells (PSCs).
• The findings reveal the underlying physical mechanisms of solid-state modification in CsSnI₃ films without organic solvents.