Soft X-ray irradiation effect on surface structure of CH&lt;inf&gt;3&lt;/inf&gt;NH&lt;inf&gt;3&lt;/inf&gt;PbI&lt;inf&gt;3&lt;/inf&gt; perovskite in multi-film stack device

Keisuke, Motoki; Miyazawa, Yu; Kobayashi, Daisuke; Ikegami, Machiko; Miyasaka, Tsutomu; Yamamoto, Tomoko; Hirose, Kazuyuki

doi:10.1109/pvsc.2016.7749904

Cited by 4 publications

(6 citation statements)

References 14 publications

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“…Lack of direct experimental signatures from MA may be attributed to the low photoionization cross sections of light elements; consequently, signals of C, N, and H atoms are difficult to detect at high photon energies in hard X-ray photoelectron spectroscopy (HAXPES). 31 Computed valence spectra provide a qualitative agreement with experiment if the DOS peaks are broadened with a 0.3−0.5 eV wide Gaussian function. 32,33 Such an ad hoc way to account for the effect of molecular motion does not provide insights into the contributing atomic species.…”

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confidence: 53%

Density of States Broadening in CH₃NH₃PbI₃ Hybrid Perovskites Understood from ab Initio Molecular Dynamics Simulations

et al. 2018

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Lead-halide perovskites are the promising materials in optoelectronic devices for their unique properties including direct band gap, strong light absorption, high carrier mobility and low fabrication cost. Here, by using ab inito molecular dynamics and electronic structure calculations, we report a systematic study on the broadening density of states (DOS) deep in the valence bands that has been experimentally observed but absent in static calculations. We quantify the broadening DOS reduction from cubic phase to lower temperature tetragonal and orthorhombic phases and attribute observed effects to the molecular vibrations and the anharmonicity of iodine atoms motion. Specifically, the MA cations' vibrations are strongly linked to the moderate C−N stretch and CH 3 bend, as well as the strong CH 3 and NH + 3 stretches. These results present a theoretical perspective on the structural dynamics in lead-halide perovskites which may be valuable for future studies toward desired functionalities in perovskite-based optoelectronic devices.

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confidence: 53%

Density of States Broadening in CH₃NH₃PbI₃ Hybrid Perovskites Understood from ab Initio Molecular Dynamics Simulations

et al. 2018

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“…To study whether a ligand polymerization reaction has taken place in the plasma-treated NC films, we performed nuclear magnetic resonance (NMR) measurements. Figure 3a shows the 13 C spectra of pure OA, pure OAm, untreated NCs, and treated NCs. Spectra of pure OA, pure OAm, and untreated CsPbBr 3 NCs are measured using liquid samples.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…Tetramethyl silane (TMS) was used as reference for 13 C spectra. To obtain sufficient sample for CPMAS-NMR analysis, 70 pieces of glass (8 × 8 cm 2 ) were used for plasma treatment.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

“…In addition, a large X-ray absorption cross section for the heavy atoms (Pb, Br, and I) in the NCs also causes them to easily decompose and quench their fluorescence. 12,13 In this work, we demonstrate a simple additive-free approach to enhance the stability of CsPbX 3 NC films. As illustrated in Scheme 1, the polymerization of double bonds in the typical ligands of oleic acid (OA) and oleylamine (OAm) on the compact NCs surface can be induced by mild plasma irradiation.…”

Section: ■ Introductionmentioning

confidence: 99%

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Giant Stability Enhancement of CsPbX₃ Nanocrystal Films by Plasma-Induced Ligand Polymerization

Wang

Zhu

Liu

et al. 2019

ACS Appl. Mater. Interfaces

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All-inorganic CsPbX 3 (X = Cl, Br, and I) nanocrystals (NCs) are emerging as attractive semiconductor materials because of their outstanding optical properties. The low resistance of CsPbX 3 NCs to light, heat, oxygen, and water has been recognized as a major obstacle to their practical applications. Here, we demonstrate that the stability of CsPbX 3 NC films can be dramatically enhanced by Ar plasma treatment. It is revealed that plasma irradiation can induce ligand polymerization in the NC films if the ligands contain unsaturated carbon bonds. The ligand polymerization leads to encapsulation of the NCs in the ligand polymers. Because of the precise localization of the in situ ligand polymerization under plasma irradiation and the high NC content in the films without extra additives, the polymerized area can be precisely defined down to several micrometers. This enables easy fabrication of high-resolution NC pixels for next generation displays.

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“…11−22 While the PCE achieved in laboratory environments is encouraging in view of commercial applications, the longterm stability of the samples remains a critical issue. 23−26 For methylammonium lead iodide (MAPbI 3 ), one of the most studied metal-halide perovskites, previous X-ray photoelectron spectroscopy studies have identified sample degradation due to light irradiation, both in the visible 27 and in the X-ray 28,29 region, as well as due to exposure to air and moisture. 30 Under these conditions, MAPbI 3 may decompose into the binary phase PbI 2 .…”

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confidence: 99%

Exciton-Dominated Core-Level Absorption Spectra of Hybrid Organic–Inorganic Lead Halide Perovskites

Vorwerk

Hartmann

Cocchi

et al. 2018

J. Phys. Chem. Lett.

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In a combined theoretical and experimental work, we investigate X-ray absorption near-edge structure spectroscopy of the I L and the Pb M edges of the methylammonium lead iodide (MAPbI) hybrid inorganic-organic perovskite and its binary phase PbI. The absorption onsets are dominated by bound excitons with sizable binding energies of a few hundred millielectronvolts and pronounced anisotropy. The spectra of both materials exhibit remarkable similarities, suggesting that the fingerprints of core excitations in MAPbI are essentially given by its inorganic component, with negligible influence from the organic groups. The theoretical analysis complementing experimental observations provides the conceptual insights required for a full characterization of this complex material.

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Soft X-ray irradiation effect on surface structure of CH<inf>3</inf>NH<inf>3</inf>PbI<inf>3</inf> perovskite in multi-film stack device

Cited by 4 publications

References 14 publications

Density of States Broadening in CH₃NH₃PbI₃ Hybrid Perovskites Understood from ab Initio Molecular Dynamics Simulations

Density of States Broadening in CH₃NH₃PbI₃ Hybrid Perovskites Understood from ab Initio Molecular Dynamics Simulations

Giant Stability Enhancement of CsPbX₃ Nanocrystal Films by Plasma-Induced Ligand Polymerization

Exciton-Dominated Core-Level Absorption Spectra of Hybrid Organic–Inorganic Lead Halide Perovskites

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Soft X-ray irradiation effect on surface structure of CH<inf>3</inf>NH<inf>3</inf>PbI<inf>3</inf> perovskite in multi-film stack device

Cited by 4 publications

References 14 publications

Density of States Broadening in CH3NH3PbI3 Hybrid Perovskites Understood from ab Initio Molecular Dynamics Simulations

Density of States Broadening in CH3NH3PbI3 Hybrid Perovskites Understood from ab Initio Molecular Dynamics Simulations

Giant Stability Enhancement of CsPbX3 Nanocrystal Films by Plasma-Induced Ligand Polymerization

Exciton-Dominated Core-Level Absorption Spectra of Hybrid Organic–Inorganic Lead Halide Perovskites

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Density of States Broadening in CH₃NH₃PbI₃ Hybrid Perovskites Understood from ab Initio Molecular Dynamics Simulations

Density of States Broadening in CH₃NH₃PbI₃ Hybrid Perovskites Understood from ab Initio Molecular Dynamics Simulations

Giant Stability Enhancement of CsPbX₃ Nanocrystal Films by Plasma-Induced Ligand Polymerization