Coevaporated Formamidinium Tin Triiodide with Suppressed p‑Type Self-Doping

Area of Science:

• Materials Science
• Solid-State Chemistry
• Photovoltaics

Background:

• Tin-based perovskites are promising for solar cells but suffer from instability.
• Oxidation and self-doping of tin lead to defects and poor performance.

Purpose of the Study:

• To develop a stable and high-quality tin-based perovskite thin film.
• To investigate a novel synthesis method for formamidinium tin triiodide (FASnI₃) films.

Main Methods:

• Solvent-free coevaporation of FASnI₃ precursors.
• Characterization of thin film crystallinity and bandgap.
• Analysis of oxidation and self-doping tendencies.

Main Results:

• Achieved highly crystalline FASnI₃ thin films with a bandgap of ~1.31 eV.
• Demonstrated reduced Sn²⁺ to Sn⁴⁺ oxidation and self-doping.
• Observed improved resistance to defect formation in the synthesized films.

Conclusions:

• Solvent-free coevaporation is a viable method for producing high-quality Sn-based perovskite films.
• The developed process enhances material stability and reduces defects.
• This approach holds promise for efficient and durable perovskite solar cells.