Collective Behavior of Molecular Dipoles in CH3NH3PbI3

Goehry, Charles; Nemneş, George Alexandru; Manolescu, Andrei

doi:10.1021/acs.jpcc.5b05823

Cited by 48 publications

(57 citation statements)

References 34 publications

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“…Recent reports show that even without defects, hybrid perovskite crystals display significant structural fluctuations [3][4][5][6][7][8][9][10][11][12][13][14]. The organic molecular cation plays an important role in the structural fluctuations of the hybrid perovskites, as supported by dielectric measurements, neutron scattering, and molecular dynamics [15][16][17][18].…”

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confidence: 89%

Local Polar Fluctuations in Lead Halide Perovskite Crystals

et al. 2017

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Hybrid lead-halide perovskites have emerged as an excellent class of photovoltaic materials. Recent reports suggest that the organic molecular cation is responsible for local polar fluctuations that inhibit carrier recombination. We combine low-frequency Raman scattering with first-principles molecular dynamics (MD) to study the fundamental nature of these local polar fluctuations. Our observations of a strong central peak in the cubic phase of both hybrid (CH_{3}NH_{3}PbBr_{3}) and all-inorganic (CsPbBr_{3}) lead-halide perovskites show that anharmonic, local polar fluctuations are intrinsic to the general lead-halide perovskite structure, and not unique to the dipolar organic cation. MD simulations indicate that head-to-head Cs motion coupled to Br face expansion, occurring on a few hundred femtosecond time scale, drives the local polar fluctuations in CsPbBr_{3}.

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confidence: 89%

Local Polar Fluctuations in Lead Halide Perovskite Crystals

et al. 2017

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“…Some theoretical works investigated the distribution and rotation of organic cations, [208][209][210][211][212][213][214] and found that rotational relaxation time in the tetragonal and cubic phases are 32.7 and 15.2 ps, respectively. [208] The rotational motions of MA cations suppressed the thermal conductivity. [213] The energy landscape and the band structure are relatively insensitive to the A-cation orientation.…”

Section: Distribution and Rotation Of Organic Cationsmentioning

confidence: 99%

Theoretical Progress on the Relationship between the Structures and Properties of Perovskite Solar Cells

Wang

Tong

Zhang

et al. 2020

Advcd Theory and Sims

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Organic–inorganic lead halide perovskite solar cells have attracted great attention due to their high conversion efficiency, easy preparation, and low cost. In spite of impressive development, some fundamental scientific issues regarding perovskites have not been resolved, such as the inclusion of toxic Pb, their poor stability under moisture, oxygen, heat, and/or light conditions, and their hysteretic current–voltage behavior. In the past few years, theoretical approaches have been extensively and successfully applied to the investigation of perovskite solar cells. Here, the current theoretical progress in perovskite photovoltaic applications is summarized from a theoretical perspective, including important theoretical results in fundamental structures and properties, computational design of perovskites by high throughput calculation and machine learning, hysteresis‐related ion migration, compositional substitution and mixing, surface reconstruction, mechanisms of degradation and passivation, interface carrier recombination, and the distribution and rotation of organic cations caused polarization and domain.

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“…Ferroelectricity is another potential cause considered for the observed hysteresis. Yet it is a controversial hypothesis, as the time-scales involved are typically below ms [26], which lends the idea of microscopic ferroelectricity [27]. It is important to note, however, that capacitive effects alone cannot reproduce different pre-conditioning effects induced by initial light soaking and pre-poling by different biases [19].…”

Section: Introductionmentioning

confidence: 99%

Dynamic electrical behavior of halide perovskite based solar cells

Nemneş

Beșleagă

Tomulescu

et al. 2017

Solar Energy Materials and Solar Cells

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A dynamic electrical model is introduced to investigate the hysteretic effects in the I-V characteristics of perovskite based solar cells. By making a simple ansatz for the polarization relaxation, our model is able to reproduce qualitatively and quantitatively detailed features of measured I-V characteristics. Pre-poling effects are discussed, pointing out the differences between initially over- and under-polarized samples. In particular, the presence of the current over-shoot observed in the reverse characteristics is correlated with the solar cell pre-conditioning. Furthermore, the dynamic hysteresis is analyzed with respect to changing the bias scan rate, the obtained results being consistent with experimentally reported data: the hysteresis amplitude is maximum at intermediate scan rates, while at very slow and very fast ones it becomes negligible. The effects induced by different relaxation time scales are assessed. The proposed dynamic electrical model offers a comprehensive view of the solar cell operation, being a practical tool for future calibration of tentative microscopic descriptions.Comment: 8 pages, 6 figures, Supplemental material, to appear in Solar Energy Materials & Solar Cell

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Collective Behavior of Molecular Dipoles in CH₃NH₃PbI₃

Cited by 48 publications

References 34 publications

Local Polar Fluctuations in Lead Halide Perovskite Crystals

Local Polar Fluctuations in Lead Halide Perovskite Crystals

Theoretical Progress on the Relationship between the Structures and Properties of Perovskite Solar Cells

Dynamic electrical behavior of halide perovskite based solar cells

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