Surender Kumar, Torben Steenbock and Gabriel Bester*,
{"title":"Origin of the High-Frequency Shoulder in the Raman Spectra of CdSe Quantum Dots","authors":"Surender Kumar, Torben Steenbock and Gabriel Bester*, ","doi":"10.1021/acs.jpclett.4c0233510.1021/acs.jpclett.4c02335","DOIUrl":null,"url":null,"abstract":"<p >The origin of the high-frequency shoulder (HFS) observed above the longitudinal optical (LO) peak around 230 cm<sup>–1</sup> in the Raman spectra of CdSe quantum dots (QDs) has been the subject of intense debate. We use state-of-the-art <i>ab initio</i> density functional theory applied to small CdSe QDs with various realistic surface passivations and find an intense Raman signal around 230 cm<sup>–1</sup>, which corresponds to a stretching vibration of a defective 2-fold coordinated Se atom. We interpret this signal as being the origin of the HFS. Since the signal disappears in fully passivated and defect-free (magic size cluster) structures, it can be used as a fingerprint to distinguish defective from nondefective structures.</p>","PeriodicalId":62,"journal":{"name":"The Journal of Physical Chemistry Letters","volume":null,"pages":null},"PeriodicalIF":4.8000,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acs.jpclett.4c02335","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"The Journal of Physical Chemistry Letters","FirstCategoryId":"1","ListUrlMain":"https://pubs.acs.org/doi/10.1021/acs.jpclett.4c02335","RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"CHEMISTRY, PHYSICAL","Score":null,"Total":0}
引用次数: 0
Abstract
The origin of the high-frequency shoulder (HFS) observed above the longitudinal optical (LO) peak around 230 cm–1 in the Raman spectra of CdSe quantum dots (QDs) has been the subject of intense debate. We use state-of-the-art ab initio density functional theory applied to small CdSe QDs with various realistic surface passivations and find an intense Raman signal around 230 cm–1, which corresponds to a stretching vibration of a defective 2-fold coordinated Se atom. We interpret this signal as being the origin of the HFS. Since the signal disappears in fully passivated and defect-free (magic size cluster) structures, it can be used as a fingerprint to distinguish defective from nondefective structures.
期刊介绍：
The Journal of Physical Chemistry (JPC) Letters is devoted to reporting new and original experimental and theoretical basic research of interest to physical chemists, biophysical chemists, chemical physicists, physicists, material scientists, and engineers. An important criterion for acceptance is that the paper reports a significant scientific advance and/or physical insight such that rapid publication is essential. Two issues of JPC Letters are published each month.
京公网安备 11010802042870号
京ICP备2023020795号-1
分享
求助内容：
应助结果提醒方式：
扫码关注我们
