Mixed-halide perovskite alloys $\text{CsPb}(\text{I}_{1-x}^{}\text{Br}_x^{})_3^{}$ and $\text{CsPb}(\text{Br}_{1-x}^{}\text{Cl}_x^{})_3^{}$: New insight of configuration entropy effect from first principles and phase diagrams
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| Main Authors: | , , , , , , , , , , |
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| Format: | Preprint |
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2024
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| _version_ | 1866929259499487232 |
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| author | Pan, Fang Zhai, Junni Chen, Jinyu Yang, Lin Dong, Hua Yuan, Fang Jiang, Zhuangde Ren, Wei Ye, Zuo-Guang Zhang, Guo-Xu Li, Jingrui |
| author_facet | Pan, Fang Zhai, Junni Chen, Jinyu Yang, Lin Dong, Hua Yuan, Fang Jiang, Zhuangde Ren, Wei Ye, Zuo-Guang Zhang, Guo-Xu Li, Jingrui |
| contents | Stability is one of the key issues in mixed-halide perovskite alloys which are promising in emergent optoelectronics. Previous density-functional-theory (DFT) and machine learning studies indicate that the formation-energy convex hulls of these materials are very shallow, and stable alloy compositions are rare. In this work, we revisit this problem using DFT with special focus on the effects of configuration and vibration entropies. Allowed by the $20$-atomic models for the $\text{CsPb}(\text{I}_{1-x}^{}\text{Br}_x^{})_3^{}$ and $\text{CsPb}(\text{Br}_{1-x}^{}\text{Cl}_x^{})_3^{}$ series, the partition functions and therewith thermodynamic state functions are calculated by traversing all possible mixed-halide configurations. We can thus evaluate the temperature- and system-dependent configuration entropy, which largely corrects the conventional approach based on the ideal solution model. Finally, temperature-composition phase diagrams that include $α$, $β$, $γ$ and $δ$ phases of both alloys are constructed based on the free energy data, for which the contribution of phonon vibrations is included. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2402_19274 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Mixed-halide perovskite alloys $\text{CsPb}(\text{I}_{1-x}^{}\text{Br}_x^{})_3^{}$ and $\text{CsPb}(\text{Br}_{1-x}^{}\text{Cl}_x^{})_3^{}$: New insight of configuration entropy effect from first principles and phase diagrams Pan, Fang Zhai, Junni Chen, Jinyu Yang, Lin Dong, Hua Yuan, Fang Jiang, Zhuangde Ren, Wei Ye, Zuo-Guang Zhang, Guo-Xu Li, Jingrui Materials Science Stability is one of the key issues in mixed-halide perovskite alloys which are promising in emergent optoelectronics. Previous density-functional-theory (DFT) and machine learning studies indicate that the formation-energy convex hulls of these materials are very shallow, and stable alloy compositions are rare. In this work, we revisit this problem using DFT with special focus on the effects of configuration and vibration entropies. Allowed by the $20$-atomic models for the $\text{CsPb}(\text{I}_{1-x}^{}\text{Br}_x^{})_3^{}$ and $\text{CsPb}(\text{Br}_{1-x}^{}\text{Cl}_x^{})_3^{}$ series, the partition functions and therewith thermodynamic state functions are calculated by traversing all possible mixed-halide configurations. We can thus evaluate the temperature- and system-dependent configuration entropy, which largely corrects the conventional approach based on the ideal solution model. Finally, temperature-composition phase diagrams that include $α$, $β$, $γ$ and $δ$ phases of both alloys are constructed based on the free energy data, for which the contribution of phonon vibrations is included. |
| title | Mixed-halide perovskite alloys $\text{CsPb}(\text{I}_{1-x}^{}\text{Br}_x^{})_3^{}$ and $\text{CsPb}(\text{Br}_{1-x}^{}\text{Cl}_x^{})_3^{}$: New insight of configuration entropy effect from first principles and phase diagrams |
| topic | Materials Science |
| url | https://arxiv.org/abs/2402.19274 |