Size-controlled ex-nihilo ferromagnetism in capped CdSe quantum dots

Mohindar S. Seehra; Prasanta Dutta; Sonnathi Neeleshwar; Yang Yuan Chen; Cheng Lung Chen; Shang Wei Chou; Chia Chun Chen; Chung Li Dong; Ching Lin Chang

doi:10.1002/adma.200702382

Size-controlled ex-nihilo ferromagnetism in capped CdSe quantum dots

Mohindar S. Seehra, Prasanta Dutta, Sonnathi Neeleshwar, Yang Yuan Chen, Cheng Lung Chen, Shang Wei Chou, Chia Chun Chen, Chung Li Dong, Ching Lin Chang

Research output: Contribution to journal › Article › peer-review

60 Scopus citations

Abstract

The observation of RTEM in CdSe quantum dots (QD) capped with TOPO was investigated. XPS and EXAFS studies on TOPO passivated CdSe QDs have shown that TOPO binds only at the Cd site and that the surface coverage on the Cd sites varies from a high of about 60% for D=2 nm to about 35% for D>3 nm. The mechanism of charge transfer from Cd to TOPO invoked in the interpretation was measured in some of the samples using XANES (X-ray absorption near-edge structure) and EXAFS (extended X-ray absorption fine structure) spectra of TOPO-capped CdSe QDs. It was observed that with the reduction in size D of the CdSe QDs, an increase in the d-hole population of the Cd 4d band is possible as a result of the charge redistribution with the capping agent TOPO.

Original language	English (US)
Pages (from-to)	1656-1660
Number of pages	5
Journal	Advanced Materials
Volume	20
Issue number	9
DOIs	https://doi.org/10.1002/adma.200702382
State	Published - May 5 2008
Externally published	Yes

ASJC Scopus subject areas

General Materials Science
Mechanics of Materials
Mechanical Engineering

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title = "Size-controlled ex-nihilo ferromagnetism in capped CdSe quantum dots",

abstract = "The observation of RTEM in CdSe quantum dots (QD) capped with TOPO was investigated. XPS and EXAFS studies on TOPO passivated CdSe QDs have shown that TOPO binds only at the Cd site and that the surface coverage on the Cd sites varies from a high of about 60% for D=2 nm to about 35% for D>3 nm. The mechanism of charge transfer from Cd to TOPO invoked in the interpretation was measured in some of the samples using XANES (X-ray absorption near-edge structure) and EXAFS (extended X-ray absorption fine structure) spectra of TOPO-capped CdSe QDs. It was observed that with the reduction in size D of the CdSe QDs, an increase in the d-hole population of the Cd 4d band is possible as a result of the charge redistribution with the capping agent TOPO.",

author = "Seehra, {Mohindar S.} and Prasanta Dutta and Sonnathi Neeleshwar and Chen, {Yang Yuan} and Chen, {Cheng Lung} and Chou, {Shang Wei} and Chen, {Chia Chun} and Dong, {Chung Li} and Chang, {Ching Lin}",

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doi = "10.1002/adma.200702382",

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T1 - Size-controlled ex-nihilo ferromagnetism in capped CdSe quantum dots

AU - Seehra, Mohindar S.

AU - Dutta, Prasanta

AU - Neeleshwar, Sonnathi

AU - Chen, Yang Yuan

AU - Chen, Cheng Lung

AU - Chou, Shang Wei

AU - Chen, Chia Chun

AU - Dong, Chung Li

AU - Chang, Ching Lin

PY - 2008/5/5

Y1 - 2008/5/5

N2 - The observation of RTEM in CdSe quantum dots (QD) capped with TOPO was investigated. XPS and EXAFS studies on TOPO passivated CdSe QDs have shown that TOPO binds only at the Cd site and that the surface coverage on the Cd sites varies from a high of about 60% for D=2 nm to about 35% for D>3 nm. The mechanism of charge transfer from Cd to TOPO invoked in the interpretation was measured in some of the samples using XANES (X-ray absorption near-edge structure) and EXAFS (extended X-ray absorption fine structure) spectra of TOPO-capped CdSe QDs. It was observed that with the reduction in size D of the CdSe QDs, an increase in the d-hole population of the Cd 4d band is possible as a result of the charge redistribution with the capping agent TOPO.

AB - The observation of RTEM in CdSe quantum dots (QD) capped with TOPO was investigated. XPS and EXAFS studies on TOPO passivated CdSe QDs have shown that TOPO binds only at the Cd site and that the surface coverage on the Cd sites varies from a high of about 60% for D=2 nm to about 35% for D>3 nm. The mechanism of charge transfer from Cd to TOPO invoked in the interpretation was measured in some of the samples using XANES (X-ray absorption near-edge structure) and EXAFS (extended X-ray absorption fine structure) spectra of TOPO-capped CdSe QDs. It was observed that with the reduction in size D of the CdSe QDs, an increase in the d-hole population of the Cd 4d band is possible as a result of the charge redistribution with the capping agent TOPO.

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Size-controlled ex-nihilo ferromagnetism in capped CdSe quantum dots

Abstract

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