Stress effect on atomic diffusion

Yang, Fuqian

doi:10.1016/j.ssc.2023.115244

Cited by 2 publications

(2 citation statements)

References 35 publications

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“…with D 0 as a pre-exponential factor, and Q is the activation energy. In general, the activation energy for the motion of ions/atoms at the stress-free state is the difference of the potential energies between the activated state (the saddle point) and the equilibrium state [47], which depends on the interaction between the ions/atoms and adjacent ions/atoms. This interaction significantly depends on the structure of crystals.…”

Section: Discussionmentioning

confidence: 99%

Effects of size mismatch of halide ions on the phase stability of mixed halide perovskites

Yang

2024

Phys. Scr.

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The phase stability of mixed halide perovskites plays a vital role in the performance and reliability of perovskite-based devices and systems. In this work, we incorporate the contribution of the strain energy due to the size mismatch of halogen ions in Gibbs free energy for the analysis of the phase stability of mixed halide perovskites. Analytical expressions of the chemical potentials of halide ions in mixed halide perovskites are derived and used to determine the critical atomic fractions of halide ions for the presence of spinodal decomposition (phase instability). The numerical analysis of CH3NH3PbIxBr3-x mixed halide perovskite reveals the important role of the mismatch strain from halogen ions in controlling the phase instability of mixed halide perovskite, i.e., increasing the mismatch strain widens the range of x for the phase separation of mixed halide perovskites. To mitigate the phase instability associated with the strain energy from intrinsic size mismatch and/or light-induced expansion, strain and/or field engineering, such as high pressure, can be likely applied to introduce strain and/or field gradient to counterbalance the strain gradient by the mismatch strain and/or light-induced expansion.

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Section: Discussionmentioning

confidence: 99%

Effects of size mismatch of halide ions on the phase stability of mixed halide perovskites

Yang

2024

Phys. Scr.

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“…Dong and co-authors derived an equation by considering the chemical potential and diffusivity affected by stress to interpret the stress-diffusion coupling effects during oxidation [37]. Using statistical thermodynamics, Yang also derived an analytical expression of diffusivity and the net flux of atoms, which brings out stress's effects on the diffusion of atoms in a stress field [38]. A comparison of the predicted oxygen concentration distribution in pure titanium between the present phase-field model and Dong's model is shown in Figure 12.…”

Section: The Influence Of the Stress Gradientmentioning

confidence: 99%

Investigation of the Effect of Stress on Oxygen Diffusion in Pure Titanium Using a Phase-Field Model

Wang,

Zhang,

Yang

2024

Materials

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Diffusion plays a vital role during the fabrication of many materials. It is a well-known fact that stress can influence diffusion behavior. In order to optimize material processing techniques, a quantitative evaluation of the effect of stress on diffusion is essentially required. By analyzing the free energy change in a Ti-O system during diffusion, a phase-field model was developed to address this issue. Using this model, the diffusion of oxygen atoms in pure titanium under different stress states was investigated. It was observed that the true equilibrium concentration of oxygen was proportional to its hydrostatic pressure. Tensile stress can increase the oxygen concentration. This raise in concentration decreased with temperature. However, the promotion of diffusion can be attained in deeper regions at a higher temperature. On the contrary, compressive stress inhibited the diffusion of oxygen in pure titanium. Under a certain compressive stress, the decrease in the oxygen concentration at the surface layer was more significant at a lower temperature, while a decrease could be observed at a deeper distance from the surface at a higher temperature. A thermodynamic explanation of the effect of stress on diffusion was given based on the proposed phase-field model.

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Stress effect on atomic diffusion

Cited by 2 publications

References 35 publications

Effects of size mismatch of halide ions on the phase stability of mixed halide perovskites

Effects of size mismatch of halide ions on the phase stability of mixed halide perovskites

Investigation of the Effect of Stress on Oxygen Diffusion in Pure Titanium Using a Phase-Field Model

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