Topic
Perovskite (structure)
About: Perovskite (structure) is a research topic. Over the lifetime, 51482 publications have been published within this topic receiving 1541750 citations.
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TL;DR: High-quality perovskite monocrystalline films are successfully grown through cavitation-triggered asymmetric crystallization, enabling a simple cell structure, ITO/CH3 NH3 PbBr3 /Au, with near 100% internal quantum efficiency, promising power conversion efficiencies >5%, and superior stability for prototype cells.
Abstract: High-quality perovskite monocrystalline films are successfully grown through cavitation-triggered asymmetric crystallization. These films enable a simple cell structure, ITO/CH3 NH3 PbBr3 /Au, with near 100% internal quantum efficiency, promising power conversion efficiencies (PCEs) >5%, and superior stability for prototype cells. Furthermore, the monocrystalline devices using a hole-transporter-free structure yield PCEs ≈6.5%, the highest among other similar-structured CH3 NH3 PbBr3 solar cells to date.
284 citations
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TL;DR: In this paper, the authors report on ab initio electronic structure and Car-Parrinello molecular dynamics simulations for several structural models of the prototype MAPbI3 perovskite for solar cells applications.
Abstract: We report on ab initio electronic structure and Car–Parrinello molecular dynamics simulations for several structural models of the prototype MAPbI3 perovskite for solar cells applications. We considered both configurations having a preferred orientation of the MA cations, giving rise to a net dipole alignment, and configurations with an isotropic distribution of the MA cations, respectively representative of polar (ferroelectric) and apolar (antiferroelectric) structures. Our calculations demonstrate the preferred stability of a set of polar structures over apolar ones, with an energy difference within 0.1 eV and a conversion barrier within 0.2 eV per unit cell (four MAPbI3), thus possibly accessible at room temperature. Ferroelectric-like orientations lead to a quasi I4cm structure for the inorganic component, characterized by lack of inversion symmetry, while the antiferroelectric-like orientations are associated to a quasi I4/mcm structure. Ab initio molecular dynamics simulations on the polar structur...
284 citations
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TL;DR: It is found that even in globally centrosymmetric structures the dynamics of the coupled inorganic-organic degrees of freedom give rise to a spatially local Rashba effect which fluctuates on the subpicosecond time scale typical of the methylammonium cation dynamics.
Abstract: The presence of a Rashba band-splitting mechanism mediated by spin–orbit coupling and breaking of inversion symmetry has been suggested as a possible cause for the reduced recombination rates observed in organohalide perovskites. Here, we investigate the interplay of electronic and nuclear degrees of freedom in defining the Rashba splitting in realistic MAPbI3 models. Our simulations disclose a “dynamical Rashba effect”, allowing for a quantification of its magnitude under thermal conditions. We find that even in globally centrosymmetric structures the dynamics of the coupled inorganic–organic degrees of freedom give rise to a spatially local Rashba effect which fluctuates on the subpicosecond time scale typical of the methylammonium cation dynamics. This effect is progressively quenched in globally centrosymmetric structures, likely representing the MAPbI3 perovskite at room temperature, on increasing the probed spatial scale up to 32 MAPbI3 units (∼3 nm size) because of the incoherent nuclear thermal mo...
283 citations
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TL;DR: It is proposed that a narrow electronic state of significant oxygen 2p character near the Fermi level exchanges electrons with the oxygen adsorbates, highlighting the importance of surface anion-redox chemistry in oxygen-deficient transition-metal oxides.
Abstract: Surface redox centres in metal oxides play a key role in catalytic performance, and the conventional view is that the transition-metal cations dominate this behaviour. Here, the authors perform an in operando spectroscopic study, and find that oxygen anions are a significant redox partner to molecular oxygen.
283 citations
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TL;DR: A computational investigation of the CH3NH3PbI3/CH3NH 3PbBr3 alloy from density functional theory with a thermodynamic analysis performed within the generalized quasi-chemical approximation finds a large miscibility gap.
Abstract: The formation of solid-solutions of iodide, bromide, and chloride provides the means to control the structure, band gap, and stability of hybrid halide perovskite semiconductors for photovoltaic applications. We report a computational investigation of the CH3NH3PbI3/CH3NH3PbBr3 alloy from density functional theory with a thermodynamic analysis performed within the generalized quasi-chemical approximation. We construct the phase diagram and identify a large miscibility gap, with a critical temperature of 343 K. The observed photoinstability in some mixed-halide solar cells is explained by the thermodynamics of alloy formation, where an initially homogeneous solution is subject to spinodal decomposition with I and Br-rich phases, which is further complicated by a wide metastable region defined by the binodal line.
283 citations