Phase stability and impact of water on CsSnI<sub>3</sub> perovskite

Li, Wenbiao; Liu, Ping; Wang, Fei; Pan, Lijia; Guo, Haizhong; Chen, Yongsheng; Yang, Shi‐e

doi:10.35848/1882-0786/ab998e

Cited by 10 publications

(14 citation statements)

References 34 publications

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“…We examine the effect of the isolated H 2 O molecule on the phase transformation to understand the moisture-induced phase instability . Many of the previous DFT studies focused on the interaction of H 2 O with surfaces of metal halide perovskites and its effect on the phase stability. − However, the effects of H 2 O molecules in the bulk system and their impact on the phase stability have not been well studied. Figure a shows the optimized structures of H 2 O in γ- and δ-CsPbI 3 .…”

Section: Resultsmentioning

confidence: 99%

Influence of External Conditions on the Black-to-Yellow Phase Transition of CsPbI₃ Based on First-Principles Calculations: Pressure and Moisture

et al. 2023

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All-inorganic CsPbI 3 perovskite has emerged as a promising candidate for next-generation solar cells. However, owing to the poor structural stability of black phase CsPbI 3 perovskite at room temperature, it spontaneously transforms to the yellow, photoinactive, nonperovskite phase at room temperature, limiting further development of CsPbI 3 perovskite solar cells. To better understand the mechanism driving such undesirable phase transformation, we examine the thermodynamics and kinetics associated with γ-to-δ phase transformation using density functional theory calculation. A solid-state nudged elastic band method was employed to find minimum energy pathways assuming a concerted solid-state phase transformation between these two phases. The gas molecules representing atmospheric (H 2 O, O 2 , and N 2 ) and inert (Ar) ambient environments, as well as applied external pressure, were considered to examine the influence of external conditions on the black-to-yellow phase transition. Our calculation reveals that, with increasing pressure, the thermodynamic driving force for converting the γ-phase to the δ-phase increases, whereas a larger activation energy must be overcome for the phase transition to occur. We also investigate the moisture-induced phase transformation with an H 2 O molecule and its dissociated species (H + /OH − ) and demonstrate that the reaction energy barriers can be significantly lowered in the presence of H 2 O or OH − . On the other hand, other nonpolar species (O 2 , N 2 , and Ar) have a negligible effect on the phase transformation kinetics, while they might reduce the thermodynamic driving force for the phase transformation and suppress the undesirable phase transformation. Our theoretical prediction could support recent observations that the γ-to-δ phase transformation occurs rapidly and catalytically in the presence of moisture, whereas in dry argon and dry oxygen atmospheres, the γ-CsPbI 3 remains stable.

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Section: Resultsmentioning

confidence: 99%

Influence of External Conditions on the Black-to-Yellow Phase Transition of CsPbI₃ Based on First-Principles Calculations: Pressure and Moisture

et al. 2023

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“…It was demonstrated that the surface energy of the γ-CsSnI 3 slab sliced along (202) terminated by Cs + and I − ions (2.6 meV/Å 2 ) was smaller than that terminated by Sn 2+ ions (23.1 meV/Å 2 ), which is consistent with the reported works. 23,37,38 Therefore, the models terminated by Cs + and I − ions were used in the current work. The thickness of the slab was set as 7 octahedral layers (i.e., 15 atomic layers), and a 16 Å vacuum layer was added above the slab to minimize the interaction with the mirror images.…”

Section: ■ Computational Methodsmentioning

confidence: 99%

Linearly Tailored Work Function of Orthorhombic CsSnI₃ Perovskites

et al. 2021

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Currently, the green tin halide perovskites are emerging as one of alternatives to their toxic lead halide counterparts. However, the recognized big problem hindering their application in photovoltaic devices is their inferior open-circuit voltage, which could be effectively addressed by tuning work function (Φ). Herein, we propose a strategy for tailoring the Φ of γ-CsSnI3 via surface passivation with phenylethylammonium (PEA+) and its halogen derivatives (XPEA+) by first-principles calculations. The Φ of γ-CsSnI3 is tightly correlated with the surface dipole, while the contributions from surface structure relaxation and charge exchange are negligible. Accordingly, the Φ can be linearly aligned with a slope of −1.435 and Adj. R 2 of 0.995 from 1.74 to 5.28 eV as a function of surface dipole and ligand layer coverage. Consequently, the reduced Φ causes a downward band bending to facilitate electron transfer with enhanced V OC, underscoring their potential in efficient environmentally friendly solar cells.

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“…Several computational studies have been conducted to understand the compositional effect on the water adsorption properties of halide perovskites. 28,62,[80][81][82] Li et al 62 performed a comprehensive study using DFT to investigate the effect of composition on water absorption and understand their underlying mechanism by varying A = MA + , FA + and CS + ; B = Pb 2+ , Sn 2+ ; X = I À and Br. Figure 2 shows the description of various adsorption sites along with the comparison of adsorption energies for different compositions for AI and BX 2 terminated surfaces.…”

Section: Compositional Effectsmentioning

confidence: 99%

A review on computational modeling of instability and degradation issues of halide perovskite photovoltaic materials

Bhatt

Pandey

Rajput

et al. 2023

WIREs Comput Mol Sci

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Hybrid halide perovskite solar cells have been recognized as one of the most promising future photovoltaic technologies due to their demonstrated high‐power conversion efficiency, versatile stoichiometry and low cost. However, degradation caused by environmental exposure and structural instability due to ionic defect migration hinders the commercialization of this technology. While the experimental studies try to understand the phenomenology of the degradation mechanisms and devise practical measures to improve the stability of these materials, theoretical studies have attempted to bridge the gaps in our understanding of the fundamental degradation mechanisms at different time and length scales. A deeper understanding of the physical and chemical phenomena at an atomic level through multiscale materials modeling is going to be crucial for the knowledge‐based prognosis and design of future halide perovskites. There have been increased efforts in this direction in the last few years. However, the instability fundamentals explored through atomistic modeling and simulation methods have not been reviewed comprehensively in the literature yet. Therefore, this paper is an attempt to present a critical review, while identifying the existing gaps and opportunities in the investigation of the degradation and instability issues of the halide perovskites using computational methods. The review will primarily focus on the instability caused due to the intrinsic ionic defect migration and degradation due to thermal, moisture and light exposure. The findings from the simulation studies conducted primarily using density functional theory, ab initio molecular dynamics, classical molecular dynamics and machine learning methods will be presented.This article is categorized under: Software > Molecular Modeling Structure and Mechanism > Computational Materials Science Data Science > Artificial Intelligence/Machine Learning

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Phase stability and impact of water on CsSnI₃ perovskite

Cited by 10 publications

References 34 publications

Influence of External Conditions on the Black-to-Yellow Phase Transition of CsPbI₃ Based on First-Principles Calculations: Pressure and Moisture

Influence of External Conditions on the Black-to-Yellow Phase Transition of CsPbI₃ Based on First-Principles Calculations: Pressure and Moisture

Linearly Tailored Work Function of Orthorhombic CsSnI₃ Perovskites

A review on computational modeling of instability and degradation issues of halide perovskite photovoltaic materials

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Phase stability and impact of water on CsSnI3 perovskite

Cited by 10 publications

References 34 publications

Influence of External Conditions on the Black-to-Yellow Phase Transition of CsPbI3 Based on First-Principles Calculations: Pressure and Moisture

Influence of External Conditions on the Black-to-Yellow Phase Transition of CsPbI3 Based on First-Principles Calculations: Pressure and Moisture

Linearly Tailored Work Function of Orthorhombic CsSnI3 Perovskites

A review on computational modeling of instability and degradation issues of halide perovskite photovoltaic materials

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Product

Resources

About

Phase stability and impact of water on CsSnI₃ perovskite

Influence of External Conditions on the Black-to-Yellow Phase Transition of CsPbI₃ Based on First-Principles Calculations: Pressure and Moisture

Influence of External Conditions on the Black-to-Yellow Phase Transition of CsPbI₃ Based on First-Principles Calculations: Pressure and Moisture

Linearly Tailored Work Function of Orthorhombic CsSnI₃ Perovskites