Pressures Tuning the Band Gap of Organic–Inorganic Trihalide Perovskites (MAPbBr3): A First-Principles Study

Tan, Mengping; Wang, Sanjun; Rao, Fengfei; Yang, Shi‐e; Wang, Fei

doi:10.1007/s11664-018-6653-3

Cited by 15 publications

(9 citation statements)

References 38 publications

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“…DFT analysis of bulk MAPbX 3 (Figure S2) indicates that the conduction band minimum (CBM) is comprised mainly of Pb p atomic orbitals and that the valence band maximum (VBM) is comprised mainly of Pb s and halide p orbitals, consistent with earlier studies. , The perovskite electronic structure produces a direct bandgap and strong optical transitions. , The energy separation between the two lowest-energy optical transitions in the absorbance spectra for Br NPLs (Figure C) is consistent with the computed absorption coefficients of the model perovskite NPL in vacuum (see Figure S3). For the Br NPLs, our computed absorption coefficients show a lowest energy absorption at 534 nm, which is at longer wavelength than is measured for the NPLs.…”

Section: Resultssupporting

confidence: 87%

Ligand Coverage and Exciton Delocalization Control Chiral Imprinting in Perovskite Nanoplatelets

Georgieva

Zhang

et al. 2022

J. Phys. Chem. C

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Chiral perovskites have recently generated significant interest, yet little is known about how their chiro-optical properties arise. In this study, chiral methylammonium lead halide perovskite nanoplatelets (NPLs) with varied halide and ligand compositions are prepared by using direct synthetic methods. Circular dichroism (CD) and 1H NMR studies find a nonlinear relationship between the chiroptical properties and the ratio of chiral phenylethylammonium (PEA) to achiral octylamine (OA) ligands on the NPL surface. We use density functional theory (DFT) computations and a chiral imprinted particle-in-a-box model to rationalize the experimentally observed CD spectra, and we find that the saturation of the induced chirality depends on the size of the perovskite exciton relative to the size of the ligand moleclues. Temperature-dependent CD and 1H NMR studies, combined with DFT analysis, show that both the CD intensity and sign depend strongly on the structure and orientation of the ligands. This work reveals the complex nature of chiral imprinting in perovskite nanostructures and establishes a simple physical model for ligand-induced chiral imprinting to guide the further development of chiral materials.

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Section: Resultssupporting

confidence: 87%

Ligand Coverage and Exciton Delocalization Control Chiral Imprinting in Perovskite Nanoplatelets

Georgieva

Zhang

et al. 2022

J. Phys. Chem. C

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“…The ground state of FAPbI 3 with a h111i orientation was the most stable, which is consistent with the results of calculations with the MA cation in the ground state of MAPbI 3 , due to the organic molecule being oriented in the h111i direction, where it has maximum freedom. 32,33 The most stable h111i orientation structure was different from the h100i orientation structure obtained by Weller et al 12 This can be explained by Weller et al's structure being obtained at 298 K, whereas our DFTcalculated h111i orientation was the ground state at 0 K. This divergence in the h111i orientation at low temperature may induce a locally disordered low-temperature g phase, 13 while the regular h100i orientation of the FA molecule results in a locally ordered high-temperature a phase. This rotational dynamics of FA molecular have revealed by the rst-principles molecular dynamics simulation by Carignano et al, 34 which show that at room temperature, the orientation of the sum vector is essentially (100) and should form a rotational glass at lower temperatures.…”

Section: Structural Propertiesmentioning

confidence: 99%

Structural, electronic, and optical properties of cubic formamidinium lead iodide perovskite: a first-principles investigation

2020

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“…18,25−27 Meanwhile, the band gap of MAPbBr 3 exhibits a V-shape change, namely, a red shift from ambient pressure to 0.9 GPa and then blue-shifts. 25,28,29 Upon further compression from 2 to 34.0 GPa, a reversible amorphization occurs, accompanied by the decreasing of the band gap. 25 Different from the isotropic metal ions (such as Cs + ) in the A-site of the inorganic MHPs, the pressure-induced amorphization in the organic MHPs may be derived from the directionality of MA and distortion of the PbBr 6 octahedron, leading to the large kinetic barrier in the pressure-induced phase transformation of the corner-shared octahedral perovskite into the thermally denser crystalline phases.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Edge-Shared Octahedral MAPbBr₃ via Pressure- and Temperature-Induced Multiple-Stage Processes

et al. 2023

Chem. Mater.

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Organic–inorganic halide perovskites possess flexible structures with tunable optical properties at high pressures, but the pressure-induced amorphization limits the understanding and exploration of the structure–property relationships. Herein, we report an edge-shared octahedral MAPbBr3 via multiple-stage transformation of the traditional corner-shared three-dimensional perovskites at high-pressure and high-temperature (P–T) conditions. In situ synchrotron X-ray diffraction reveals that upon heating at 8.7 GPa, the amorphized MAPbBr3 transforms into a high P–T structure above 654 K via multiple-stage crystallization. The high P–T phase is determined to be a monoclinic P2/m structure with layered edge-shared Pb–Br octahedra, which can be quenched to RT at high pressures but converts back to the initial cubic perovskite structure below 0.7 GPa under decompression. The Raman and optical measurements demonstrate that the high P–T phase has similar vibrational behavior and tunable optical properties to those of the pressure-induced amorphous phase, indicating the similarity in the local structure with the edge-shared PbBr6 octahedral frame and the MA organic cations between the high P–T phase and the amorphous state. The present results demonstrate the structural diversity and interconversion in MAPbBr3 by overcoming the large kinetic barrier derived from the anisotropic organic cations and disordering arrangement of the Pb–Br octahedra, providing new insights into the understanding of structural transitions and amorphization of halide perovskites.

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Pressures Tuning the Band Gap of Organic–Inorganic Trihalide Perovskites (MAPbBr3): A First-Principles Study

Cited by 15 publications

References 38 publications

Ligand Coverage and Exciton Delocalization Control Chiral Imprinting in Perovskite Nanoplatelets

Ligand Coverage and Exciton Delocalization Control Chiral Imprinting in Perovskite Nanoplatelets

Structural, electronic, and optical properties of cubic formamidinium lead iodide perovskite: a first-principles investigation

Synthesis of Edge-Shared Octahedral MAPbBr₃ via Pressure- and Temperature-Induced Multiple-Stage Processes

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Pressures Tuning the Band Gap of Organic–Inorganic Trihalide Perovskites (MAPbBr3): A First-Principles Study

Cited by 15 publications

References 38 publications

Ligand Coverage and Exciton Delocalization Control Chiral Imprinting in Perovskite Nanoplatelets

Ligand Coverage and Exciton Delocalization Control Chiral Imprinting in Perovskite Nanoplatelets

Structural, electronic, and optical properties of cubic formamidinium lead iodide perovskite: a first-principles investigation

Synthesis of Edge-Shared Octahedral MAPbBr3 via Pressure- and Temperature-Induced Multiple-Stage Processes

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Synthesis of Edge-Shared Octahedral MAPbBr₃ via Pressure- and Temperature-Induced Multiple-Stage Processes