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Thermodynamically Stable Orthorhombic γ-CsPbI3 Thin Films for High-Performance Photovoltaics.
J Am Chem Soc ; 140(37): 11716-11725, 2018 09 19.
Artigo em Inglês | MEDLINE | ID: mdl-30153411
All-inorganic lead halide perovskites demonstrate improved thermal stability over the organic-inorganic halide perovskites, but the cubic α-CsPbI3 with the most appropriate bandgap for light harvesting is not structurally stable at room temperature and spontaneously transforms into the undesired orthorhombic δ-CsPbI3. Here, we present a new member of black-phase thin films of all-inorganic perovskites for high-efficiency photovoltaics, the orthorhombic γ-CsPbI3 thin films with intrinsic thermodynamic stability and ideal electronic structure. Exempt from introducing organic ligands or incorporating mixed cations/anions into the crystal lattice, we stabilize the γ-CsPbI3 thin films by a simple solution process in which a small amount of H2O manipulates the size-dependent phase formation through a proton transfer reaction. Theoretical calculations coupled with experiments show that γ-CsPbI3 with a lower surface free energy becomes thermodynamically preferred over δ-CsPbI3 at surface areas greater than 8600 m2/mol and exhibits comparable optoelectronic properties to α-CsPbI3. Consequently, γ-CsPbI3-based solar cells display a highly reproducible efficiency of 11.3%, among the highest records for CsPbI3 thin-film solar cells, with robust stability in ambient atmosphere for months and continuous operating conditions for hours. Our study provides a novel and fundamental perspective to overcome the Achilles' heel of the inorganic lead iodide perovskite and opens it up for high-performance optoelectronic devices.





Texto completo: Disponível Coleções: Bases de dados internacionais Base de dados: MEDLINE Idioma: Inglês Revista: J Am Chem Soc Ano de publicação: 2018 Tipo de documento: Artigo