Temperature dependence of acoustic vibrations of CdSe and CdSe–CdS core–shell nanocrystals measured by low-frequency Raman spectroscopy
We measure the temperature dependence of breathing-mode acoustic vibrations of semiconductor nanocrystals using low-frequency Raman spectroscopy. In CdSe core-only nanocrystals, the lowest-energy l = 0 mode red-shifts with increasing temperature by ∼5% between 77–300 K. Changes to the interatomic bo...
| Main Authors: | , , |
|---|---|
| Other Authors: | |
| Format: | Article |
| Language: | en_US |
| Published: |
Royal Society of Chemistry
2017
|
| Online Access: | http://hdl.handle.net/1721.1/107952 https://orcid.org/0000-0002-1872-6251 https://orcid.org/0000-0001-9143-3140 https://orcid.org/0000-0002-6615-5342 |
| _version_ | 1811093672436957184 |
|---|---|
| author | Mork, Anna Jolene Lee, Elizabeth M. Tisdale, William |
| author2 | Massachusetts Institute of Technology. Department of Chemical Engineering |
| author_facet | Massachusetts Institute of Technology. Department of Chemical Engineering Mork, Anna Jolene Lee, Elizabeth M. Tisdale, William |
| author_sort | Mork, Anna Jolene |
| collection | MIT |
| description | We measure the temperature dependence of breathing-mode acoustic vibrations of semiconductor nanocrystals using low-frequency Raman spectroscopy. In CdSe core-only nanocrystals, the lowest-energy l = 0 mode red-shifts with increasing temperature by ∼5% between 77–300 K. Changes to the interatomic bond distances in the inorganic crystal lattice, with corresponding changes to the bulk modulus and density of the material, contribute to the observed energy shift but do not fully explain its magnitude across all nanocrystal sizes. Invariance of the Raman linewidth over the same temperature range suggests that the acoustic breathing mode is inhomogeneously broadened. The acoustic phonons of CdSe/CdS core–shell composite nanocrystals display similar qualitative behavior. However, for large core–shell nanocrystals, we observe a higher-order Raman peak at approximately twice the energy of the l = 0 mode, which we identify as a higher spherical harmonic—the n = 2, l = 0 eigenmode—rather than a two-phonon scattering event. |
| first_indexed | 2024-09-23T15:48:50Z |
| format | Article |
| id | mit-1721.1/107952 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T15:48:50Z |
| publishDate | 2017 |
| publisher | Royal Society of Chemistry |
| record_format | dspace |
| spelling | mit-1721.1/1079522022-10-02T04:18:07Z Temperature dependence of acoustic vibrations of CdSe and CdSe–CdS core–shell nanocrystals measured by low-frequency Raman spectroscopy Mork, Anna Jolene Lee, Elizabeth M. Tisdale, William Massachusetts Institute of Technology. Department of Chemical Engineering Mork, Anna Jolene Lee, Elizabeth M. Tisdale, William We measure the temperature dependence of breathing-mode acoustic vibrations of semiconductor nanocrystals using low-frequency Raman spectroscopy. In CdSe core-only nanocrystals, the lowest-energy l = 0 mode red-shifts with increasing temperature by ∼5% between 77–300 K. Changes to the interatomic bond distances in the inorganic crystal lattice, with corresponding changes to the bulk modulus and density of the material, contribute to the observed energy shift but do not fully explain its magnitude across all nanocrystal sizes. Invariance of the Raman linewidth over the same temperature range suggests that the acoustic breathing mode is inhomogeneously broadened. The acoustic phonons of CdSe/CdS core–shell composite nanocrystals display similar qualitative behavior. However, for large core–shell nanocrystals, we observe a higher-order Raman peak at approximately twice the energy of the l = 0 mode, which we identify as a higher spherical harmonic—the n = 2, l = 0 eigenmode—rather than a two-phonon scattering event. Eni-MIT Solar Frontiers Center Eni S.p.A. 2017-04-07T18:01:58Z 2017-04-07T18:01:58Z 2016-10 2016-08 Article http://purl.org/eprint/type/JournalArticle 1463-9076 1463-9084 http://hdl.handle.net/1721.1/107952 Mork, A. Jolene, Elizabeth M. Y. Lee, and William A. Tisdale. “Temperature Dependence of Acoustic Vibrations of CdSe and CdSe–CdS Core–shell Nanocrystals Measured by Low-Frequency Raman Spectroscopy.” Phys. Chem. Chem. Phys. 18.41 (2016): 28797–28801. © 2017 Royal Society of Chemistry https://orcid.org/0000-0002-1872-6251 https://orcid.org/0000-0001-9143-3140 https://orcid.org/0000-0002-6615-5342 en_US http://dx.doi.org/10.1039/c6cp05683k Physical Chemistry Chemical Physics Creative Commons Attribution 3.0 Unported license http://creativecommons.org/licenses/by/3.0/ application/pdf Royal Society of Chemistry Royal Society of Chemistry |
| spellingShingle | Mork, Anna Jolene Lee, Elizabeth M. Tisdale, William Temperature dependence of acoustic vibrations of CdSe and CdSe–CdS core–shell nanocrystals measured by low-frequency Raman spectroscopy |
| title | Temperature dependence of acoustic vibrations of CdSe and CdSe–CdS core–shell nanocrystals measured by low-frequency Raman spectroscopy |
| title_full | Temperature dependence of acoustic vibrations of CdSe and CdSe–CdS core–shell nanocrystals measured by low-frequency Raman spectroscopy |
| title_fullStr | Temperature dependence of acoustic vibrations of CdSe and CdSe–CdS core–shell nanocrystals measured by low-frequency Raman spectroscopy |
| title_full_unstemmed | Temperature dependence of acoustic vibrations of CdSe and CdSe–CdS core–shell nanocrystals measured by low-frequency Raman spectroscopy |
| title_short | Temperature dependence of acoustic vibrations of CdSe and CdSe–CdS core–shell nanocrystals measured by low-frequency Raman spectroscopy |
| title_sort | temperature dependence of acoustic vibrations of cdse and cdse cds core shell nanocrystals measured by low frequency raman spectroscopy |
| url | http://hdl.handle.net/1721.1/107952 https://orcid.org/0000-0002-1872-6251 https://orcid.org/0000-0001-9143-3140 https://orcid.org/0000-0002-6615-5342 |
| work_keys_str_mv | AT morkannajolene temperaturedependenceofacousticvibrationsofcdseandcdsecdscoreshellnanocrystalsmeasuredbylowfrequencyramanspectroscopy AT leeelizabethm temperaturedependenceofacousticvibrationsofcdseandcdsecdscoreshellnanocrystalsmeasuredbylowfrequencyramanspectroscopy AT tisdalewilliam temperaturedependenceofacousticvibrationsofcdseandcdsecdscoreshellnanocrystalsmeasuredbylowfrequencyramanspectroscopy |