Simple Solution Preparation of Cs₂SnI₆ Films and Their Applications in Solid-State DSSCs.

Area of Science:

• Materials Science
• Inorganic Chemistry
• Photovoltaics

Background:

• Cesium tin iodide (Cs₂SnI₆) is a promising material for optoelectronic applications.
• Developing stable and efficient Cs₂SnI₆-based devices requires careful control over film preparation and material stability.

Purpose of the Study:

• To investigate the solution preparation of Cs₂SnI₆ powder and films.
• To evaluate the impact of different solvents on Cs₂SnI₆ stability and film morphology.
• To explore the performance of Cs₂SnI₆ in solid-state dye-sensitized solar cells (ss-DSSCs).

Main Methods:

• Solution-based synthesis of Cs₂SnI₆ powder using CsI, SnI₂, and I₂.
• Film preparation using various solvents, including N,N-dimethylformamide (DMF), methanol, γ-butyrolactone (GBL), and ethylene glycol methyl ether (EGME).
• In situ preparation of Cs₂SnI₆ films and fabrication of ss-DSSCs.

Main Results:

• Cs₂SnI₆ powder was successfully synthesized and found to be air/thermally stable.
• Solvents like DMF and methanol caused Cs₂SnI₆ deterioration, while GBL and EGME yielded better results.
• In situ prepared Cs₂SnI₆ films showed improved orientation and purity, leading to higher ss-DSSC power conversion efficiencies (PCEs) up to 3.30%.
• A PCE of 6.14% was achieved with an additive in the Cs₂SnI₆ electrolyte, demonstrating the potential of this material.

Conclusions:

• Solvent selection is crucial for the successful preparation and stability of Cs₂SnI₆ films.
• In situ film preparation offers advantages for achieving highly pure and oriented Cs₂SnI₆ layers.
• Cs₂SnI₆-based ss-DSSCs show significant potential for photovoltaic applications, with further improvements possible through electrolyte optimization and understanding of gap state effects.