Sign of the Gap Temperature Dependence in CsPb(Br,Cl)3 Nanocrystals Determined by Cs-Rattler Mediated Electron-Phonon Coupling
Fuente:
arXiv
Gespeichert in:
| Hauptverfasser: | , , , , , , , |
|---|---|
| Format: | Preprint |
| Veröffentlicht: |
2024
|
| Schlagworte: | |
| Online-Zugang: | |
| Tags: |
Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
|
| _version_ | 1866911659397742592 |
|---|---|
| author | Fasahat, S. Fiuza-Maneiro, N. Schäfer, B. Xu, K. Gómez-Graña, S. Alonso, M. I. Polavarapu, L. Goñi, A. R. |
| author_facet | Fasahat, S. Fiuza-Maneiro, N. Schäfer, B. Xu, K. Gómez-Graña, S. Alonso, M. I. Polavarapu, L. Goñi, A. R. |
| contents | So far, the striking sign reversal in the near-ambient slope of the gap temperature dependence of colloidal CsPbCl3 perovskite nanocrystals (NCs) compared to its Br counterpart, remains unresolved. Pure bromide NCs exhibit a linear gap increase with increasing temperature, to which thermal expansion and electron-phonon interaction equally contribute. In contrast, the temperature slope for the chlorine compound gap is outspoken negative. By combining temperature and pressure-dependent photoluminescence on a series of CsPb(Br1-xClx)3 NCs, we unravel the origin of such inversion. Responsible is solely the electron-phonon interaction, undergoing a sudden change in sign and magnitude due to activation of an anomalous electron-phonon coupling mechanism linked to vibrational modes characterized by synchronous octahedral tilting and Cs rattling. This takes place in the shrunken orthorhombic NC lattice for Cl concentrations exceeding ca. 40%. We have thus clarified a puzzling result directly impacting the optoelectronic properties of lead halide perovskite NCs. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2411_13727 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Sign of the Gap Temperature Dependence in CsPb(Br,Cl)3 Nanocrystals Determined by Cs-Rattler Mediated Electron-Phonon Coupling Fasahat, S. Fiuza-Maneiro, N. Schäfer, B. Xu, K. Gómez-Graña, S. Alonso, M. I. Polavarapu, L. Goñi, A. R. Materials Science 81-05, 78-05 F.2.2; I.7 So far, the striking sign reversal in the near-ambient slope of the gap temperature dependence of colloidal CsPbCl3 perovskite nanocrystals (NCs) compared to its Br counterpart, remains unresolved. Pure bromide NCs exhibit a linear gap increase with increasing temperature, to which thermal expansion and electron-phonon interaction equally contribute. In contrast, the temperature slope for the chlorine compound gap is outspoken negative. By combining temperature and pressure-dependent photoluminescence on a series of CsPb(Br1-xClx)3 NCs, we unravel the origin of such inversion. Responsible is solely the electron-phonon interaction, undergoing a sudden change in sign and magnitude due to activation of an anomalous electron-phonon coupling mechanism linked to vibrational modes characterized by synchronous octahedral tilting and Cs rattling. This takes place in the shrunken orthorhombic NC lattice for Cl concentrations exceeding ca. 40%. We have thus clarified a puzzling result directly impacting the optoelectronic properties of lead halide perovskite NCs. |
| title | Sign of the Gap Temperature Dependence in CsPb(Br,Cl)3 Nanocrystals Determined by Cs-Rattler Mediated Electron-Phonon Coupling |
| topic | Materials Science 81-05, 78-05 F.2.2; I.7 |
| url | https://arxiv.org/abs/2411.13727 |