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Low Pressure Vapor-assisted Solution Process for Tunable Band Gap Pinhole-free Methylammonium Lead Halide Perovskite Films
Published on: September 8, 2017
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Deciphering Reaction Products in Formamidine-Based Perovskites with Methylammonium Chloride Additive
Liang Chen1, Manman Hu1, Seonghwan Lee2
1Department of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Eonyang-eup, Ulju-gun, Ulsan 44919, Republic of Korea.
Journal of the American Chemical Society
|December 11, 2023
Summary
Methylammonium chloride additives in formamidinium lead iodide perovskite solar cells create byproducts. These byproducts, specifically methyl formamidinium iodide isomers, impact crystal growth and phase stability, influencing device efficiency.
Area of Science:
- Materials Science
- Photovoltaics
- Chemical Engineering
Background:
- Formamidinium lead iodide (FAPbI3) perovskite solar cells (PSCs) utilize methylammonium chloride (MACl) for improved low-temperature phase formation.
- MACl deprotonation and volatilization generate methylamine (MA0), which can react with formamidinium (FA+).
- The chemical interactions between FAPbI3, MACl, and its byproducts are not fully understood.
Purpose of the Study:
- To investigate the chemical interactions between FAPbI3, MACl additives, and their byproducts.
- To elucidate the formation pathways and impact of methyl formamidinium (MFA+) on perovskite properties.
- To understand how these interactions affect the efficiency and stability of PSCs.
Main Methods:
- Investigated the reaction between FA+ and MA0.
- Analyzed the subsequent reaction of byproducts with PbI2.
- Grew single crystals of formamidine-based perovskites to study byproduct effects.
- Characterized crystal growth, phase stability, and band gap.
Main Results:
- The reaction between FA+ and MA0 primarily forms cis/trans-N-methyl formamidinium iodide (MFAI) isomers, with cis-MFAI being dominant.
- MFAI reacts with PbI2 to form cis-MFAPbI3 2H-phase perovskite.
- MFAI influences crystal growth, phase stability, and the band gap of formamidine-based perovskites.
Conclusions:
- The study clarifies the formation and impact of MFAI byproducts in FAPbI3 PSCs.
- MFAI significantly influences the properties of formamidine-based perovskites.
- Understanding these byproduct interactions is crucial for enhancing PSC efficiency and long-term stability.
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