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Pressure‐Dependent Mechanical and Thermal Properties of Lead‐Free Halide Double Perovskite Cs 2 AgB″X 6 (B″═In, Bi; X═Cl, Br, I)
Author(s) -
Su Jie,
Zhang Zhao,
Hou Jie,
Liu Mengyu,
Lin Zhenhua,
Hu Zhaosheng,
Chang Jingjing,
Hao Yue
Publication year - 2019
Publication title -
advanced theory and simulations
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.068
H-Index - 17
ISSN - 2513-0390
DOI - 10.1002/adts.201900164
Subject(s) - halide , perovskite (structure) , hydrostatic pressure , bulk modulus , materials science , photoelectric effect , anisotropy , bond length , analytical chemistry (journal) , crystallography , crystal structure , chemistry , thermodynamics , inorganic chemistry , physics , composite material , optoelectronics , optics , chromatography
Lead‐free halide double perovskites Cs 2 AgB″X 6 (B″═In, Bi; X═Cl, Br, I) are emerging as excellent photoelectric materials. Investigating their mechanical and thermodynamic properties under hydrostatic pressure is vital for designing high‐performance photoelectric devices. Although Cs 2 AgB″X 6 exhibits similar cubic structures, the bond length and strength characteristics of Cs 2 AgInX 6 are different to those of Cs 2 AgBiX 6 , and Cs 2 AgB″X 6 exhibits obvious mechanical anisotropic. Upon experiencing pressure, the stablility of Cs 2 AgB″X 6 is improved and without phase transition, and its bond characteristics are unified, which is different to lead halide perovskites. Compared to Cs 2 AgBiX 6 , Cs 2 AgInX 6 may be more suitable to flexible devices due to its higher shear and bulk modulus. In addition, the thermal conductivities of Cs 2 AgBiX 6 (X═Cl, Br) and Cs 2 AgBiX 6 (X═Cl, Br, I) are 0.41, 0.32, 0.37, 0.29, 0.23 W m −1 K −1 , and can be enlarged by pressure and surpass that of lead halide perovskite. Moreover, all the Cs 2 AgB″X 6 (B″═In, Bi; X═Cl, Br, I) possess the same saturated heat capacity of about 249.3 J mol −1 K −1 . These variations of mechanical and thermal properties are elucidated by the bonds. These results maybe also applicable to other double perovskites, and beneficial for designing devices with better optoelectronic performance.