{"title":"硒化镉量子点拉曼光谱中高频肩的起源","authors":"Surender Kumar, Torben Steenbock, Gabriel Bester","doi":"10.1021/acs.jpclett.4c02335","DOIUrl":null,"url":null,"abstract":"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.","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":"","citationCount":"0","resultStr":"{\"title\":\"Origin of the High-Frequency Shoulder in the Raman Spectra of CdSe Quantum Dots\",\"authors\":\"Surender Kumar, Torben Steenbock, Gabriel Bester\",\"doi\":\"10.1021/acs.jpclett.4c02335\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"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.\",\"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\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"The Journal of Physical Chemistry Letters\",\"FirstCategoryId\":\"1\",\"ListUrlMain\":\"https://doi.org/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}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"The Journal of Physical Chemistry Letters","FirstCategoryId":"1","ListUrlMain":"https://doi.org/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
摘要
在硒化镉量子点(CdSe quantum dots,QDs)的拉曼光谱中,在纵向光学峰(LO)上方约 230 cm-1 处观察到的高频肩(HFS)的起源一直是激烈争论的主题。我们将最先进的 ab initio 密度泛函理论应用于具有各种现实表面钝化的小型硒化镉量子点,发现 230 cm-1 附近有一个强烈的拉曼信号,它对应于一个有缺陷的 2 倍配位硒原子的伸缩振动。我们将这一信号解释为 HFS 的起源。由于该信号在完全钝化和无缺陷(神奇尺寸簇)结构中消失,因此可将其用作区分缺陷和非缺陷结构的指纹。
Origin of the High-Frequency Shoulder in the Raman Spectra of CdSe Quantum Dots
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.