CsSnI is a promising ecofriendly solution for energy harvesting technologies. It exists at room temperature in either a black perovskite polymorph or a yellow 1D double-chain, which irreversibly deteriorates in the air. In this work, we unveil the relative thermodynamic stability between the two structures with a first-principles sampling of the CsSnI finite-temperature phase diagram, discovering how it is driven by anomalously large quantum and anharmonic ionic fluctuations. Thanks to a comprehensive treatment of anharmonicity, the simulations deliver a remarkable agreement with known experimental data for the transition temperatures of the orthorhombic, rhombohedral, and cubic perovskite structures and the thermal expansion coefficient. We disclose how the perovskite polymorphs are the ground state above 270 K and discover an abnormal decrease in heat capacity upon heating in the cubic black perovskite. Our results also significantly downplay the Cs rattling modes' contribution to mechanical instability. The remarkable agreement with experiments validates our methodology, which can be systematically applied to all metal halides.
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http://dx.doi.org/10.1021/acs.chemmater.2c03475 | DOI Listing |
NPG Asia Mater
May 2024
Department of Chemistry, KU Leuven, Leuven, Belgium.
All-inorganic lead halide perovskites (LHPs) and their use in optoelectronic devices have been widely explored because they are more thermally stable than their hybrid organic‒inorganic counterparts. However, the active perovskite phases of some inorganic LHPs are metastable at room temperature due to the critical structural tolerance factor. For example, black phase CsPbI is easily transformed back to the nonperovskite yellow phase at ambient temperature.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
EPFL: Ecole Polytechnique Federale de Lausanne, Department of Chemistry, Rue de Industries 17, 1050, Sion, SWITZERLAND.
Carbon perovskite solar cells (C-PSCs) represent a promising photovoltaic technology that addresses the long-term operating stability needed to compete with commercial Si solar cells. However, the poor interface contacts between the carbon electrode and the perovskite result in a gap between C-PSC's performances and state-of-the-art PSCs based on metallic back electrodes. In this work, Cu (II) phthalocyanine (CuPc) was rediscovered as an effective hole-transporting material (HTM) to be coupled with carbon electrodes.
View Article and Find Full Text PDFNat Commun
January 2025
School of Physics and Technology, and Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Wuhan University, Wuhan, China.
Tin-lead perovskites provide an ideal bandgap for narrow-bandgap perovskites in all-perovskite tandem solar cells, fundamentally improving power conversion efficiency. However, light-induced degradation in ambient air is a major issue that can hinder the long-term operational stability of these devices. Understanding the specifics of what occurs during this pathway provides the direction for improving device stability.
View Article and Find Full Text PDFJ Phys Chem Lett
January 2025
School of Engineering and Materials Science, Queen Mary University of London, Mile End Road, London E1 4NS, U.K.
J Phys Chem Lett
December 2024
School of Physics Science & Information Technology, Liaocheng University, Liaocheng 252000, China.
Bismuth-based perovskite materials have attracted extensive attention due to their low toxicity and excellent optoelectronic properties. Herein, this investigation delves systematically into the influence of pressure on the structural stability, band gap evolution, and electrical transport properties of RbBiI. With the pressure increase, the band gap of the specimen gradually diminishes, attaining an optimal semiconductor band gap of 1.
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