Major electronic transition shift from bandgap to localized surface plasmon resonance in CdxHg1-xSe Alloy Nanocrystals

Dongsun Choi, Bitna Yoon, Dae Kyu Kim, Hionsuck Baik, Jong-Ho Choi, Kwang Seob Jeong

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

CdxHg1-xSe alloy nanocrystals are obtained from CdSe semiconductor nanocrystals via cation exchange. By varying the composition during the exchange process, the CdxHg1-xSe alloy nanocrystals offer a widely tunable electronic transition from visible to NIR and even to mid-IR range. The visible bandgap transition of the CdSe colloidal quantum dot gradually red-shifts to the near-IR with the addition of the Hg precursor, and then the steady-state intraband (or intersub-band) transition of the CdxHg1-xSe alloy nanocrystals appears. Finally, as the electron density is increased by successive addition of metal precursor, localized surface plasmon resonances (LSPRs) appear as a major electronic transition in the mid-IR regime. The shift of the major electronic transition from the bandgap to LSPRs infers that the exciton spatially moves to the surface from the inside of the nanocrystal through the cation change and further crystal growth. The corresponding variance of the nanocrystals' structural, compositional, optical, electrical, and magnetic properties was carefully monitored by using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), electron-dispersive X-ray (EDS) spectroscopy, time-resolved photoluminescence, photocurrent measurement, and electron paramagnetic resonance (EPR) spectroscopy, respectively. While a shift in only the bandgap has been observed in conventional quantum dots when cation-exchanged, the major oscillating transition transfers from the bandgap to the higher quantum states in CdxHg1-xSe alloy nanocrystal formed by the cation-exchange in this report. The compositional change expanding the optical range of nanocrystals from visible to mid-IR regime will provide a useful means of optimally tuning the electronic transition of nanocrystal-based applications along with improved optical selectivity demonstrated by a single intraband or LSPR peak.

Original languageEnglish
Pages (from-to)8548-8554
Number of pages7
JournalChemistry of Materials
Volume29
Issue number19
DOIs
Publication statusPublished - 2017 Oct 10

Fingerprint

Surface plasmon resonance
Electron transitions
Nanocrystals
Energy gap
Cations
Positive ions
Ion exchange
Semiconductor quantum dots
Spectroscopy
Crystallization
Photocurrents
Crystal growth
Excitons
Carrier concentration
Paramagnetic resonance
Structural properties
Energy dispersive spectroscopy
Magnetic properties
Photoluminescence
Electric properties

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Materials Chemistry

Cite this

Major electronic transition shift from bandgap to localized surface plasmon resonance in CdxHg1-xSe Alloy Nanocrystals. / Choi, Dongsun; Yoon, Bitna; Kim, Dae Kyu; Baik, Hionsuck; Choi, Jong-Ho; Jeong, Kwang Seob.

In: Chemistry of Materials, Vol. 29, No. 19, 10.10.2017, p. 8548-8554.

Research output: Contribution to journalArticle

@article{83a724a9629e4c2f8bfb944df3e618f2,
title = "Major electronic transition shift from bandgap to localized surface plasmon resonance in CdxHg1-xSe Alloy Nanocrystals",
abstract = "CdxHg1-xSe alloy nanocrystals are obtained from CdSe semiconductor nanocrystals via cation exchange. By varying the composition during the exchange process, the CdxHg1-xSe alloy nanocrystals offer a widely tunable electronic transition from visible to NIR and even to mid-IR range. The visible bandgap transition of the CdSe colloidal quantum dot gradually red-shifts to the near-IR with the addition of the Hg precursor, and then the steady-state intraband (or intersub-band) transition of the CdxHg1-xSe alloy nanocrystals appears. Finally, as the electron density is increased by successive addition of metal precursor, localized surface plasmon resonances (LSPRs) appear as a major electronic transition in the mid-IR regime. The shift of the major electronic transition from the bandgap to LSPRs infers that the exciton spatially moves to the surface from the inside of the nanocrystal through the cation change and further crystal growth. The corresponding variance of the nanocrystals' structural, compositional, optical, electrical, and magnetic properties was carefully monitored by using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), electron-dispersive X-ray (EDS) spectroscopy, time-resolved photoluminescence, photocurrent measurement, and electron paramagnetic resonance (EPR) spectroscopy, respectively. While a shift in only the bandgap has been observed in conventional quantum dots when cation-exchanged, the major oscillating transition transfers from the bandgap to the higher quantum states in CdxHg1-xSe alloy nanocrystal formed by the cation-exchange in this report. The compositional change expanding the optical range of nanocrystals from visible to mid-IR regime will provide a useful means of optimally tuning the electronic transition of nanocrystal-based applications along with improved optical selectivity demonstrated by a single intraband or LSPR peak.",
author = "Dongsun Choi and Bitna Yoon and Kim, {Dae Kyu} and Hionsuck Baik and Jong-Ho Choi and Jeong, {Kwang Seob}",
year = "2017",
month = "10",
day = "10",
doi = "10.1021/acs.chemmater.7b03813",
language = "English",
volume = "29",
pages = "8548--8554",
journal = "Chemistry of Materials",
issn = "0897-4756",
publisher = "American Chemical Society",
number = "19",

}

TY - JOUR

T1 - Major electronic transition shift from bandgap to localized surface plasmon resonance in CdxHg1-xSe Alloy Nanocrystals

AU - Choi, Dongsun

AU - Yoon, Bitna

AU - Kim, Dae Kyu

AU - Baik, Hionsuck

AU - Choi, Jong-Ho

AU - Jeong, Kwang Seob

PY - 2017/10/10

Y1 - 2017/10/10

N2 - CdxHg1-xSe alloy nanocrystals are obtained from CdSe semiconductor nanocrystals via cation exchange. By varying the composition during the exchange process, the CdxHg1-xSe alloy nanocrystals offer a widely tunable electronic transition from visible to NIR and even to mid-IR range. The visible bandgap transition of the CdSe colloidal quantum dot gradually red-shifts to the near-IR with the addition of the Hg precursor, and then the steady-state intraband (or intersub-band) transition of the CdxHg1-xSe alloy nanocrystals appears. Finally, as the electron density is increased by successive addition of metal precursor, localized surface plasmon resonances (LSPRs) appear as a major electronic transition in the mid-IR regime. The shift of the major electronic transition from the bandgap to LSPRs infers that the exciton spatially moves to the surface from the inside of the nanocrystal through the cation change and further crystal growth. The corresponding variance of the nanocrystals' structural, compositional, optical, electrical, and magnetic properties was carefully monitored by using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), electron-dispersive X-ray (EDS) spectroscopy, time-resolved photoluminescence, photocurrent measurement, and electron paramagnetic resonance (EPR) spectroscopy, respectively. While a shift in only the bandgap has been observed in conventional quantum dots when cation-exchanged, the major oscillating transition transfers from the bandgap to the higher quantum states in CdxHg1-xSe alloy nanocrystal formed by the cation-exchange in this report. The compositional change expanding the optical range of nanocrystals from visible to mid-IR regime will provide a useful means of optimally tuning the electronic transition of nanocrystal-based applications along with improved optical selectivity demonstrated by a single intraband or LSPR peak.

AB - CdxHg1-xSe alloy nanocrystals are obtained from CdSe semiconductor nanocrystals via cation exchange. By varying the composition during the exchange process, the CdxHg1-xSe alloy nanocrystals offer a widely tunable electronic transition from visible to NIR and even to mid-IR range. The visible bandgap transition of the CdSe colloidal quantum dot gradually red-shifts to the near-IR with the addition of the Hg precursor, and then the steady-state intraband (or intersub-band) transition of the CdxHg1-xSe alloy nanocrystals appears. Finally, as the electron density is increased by successive addition of metal precursor, localized surface plasmon resonances (LSPRs) appear as a major electronic transition in the mid-IR regime. The shift of the major electronic transition from the bandgap to LSPRs infers that the exciton spatially moves to the surface from the inside of the nanocrystal through the cation change and further crystal growth. The corresponding variance of the nanocrystals' structural, compositional, optical, electrical, and magnetic properties was carefully monitored by using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), electron-dispersive X-ray (EDS) spectroscopy, time-resolved photoluminescence, photocurrent measurement, and electron paramagnetic resonance (EPR) spectroscopy, respectively. While a shift in only the bandgap has been observed in conventional quantum dots when cation-exchanged, the major oscillating transition transfers from the bandgap to the higher quantum states in CdxHg1-xSe alloy nanocrystal formed by the cation-exchange in this report. The compositional change expanding the optical range of nanocrystals from visible to mid-IR regime will provide a useful means of optimally tuning the electronic transition of nanocrystal-based applications along with improved optical selectivity demonstrated by a single intraband or LSPR peak.

UR - http://www.scopus.com/inward/record.url?scp=85031023828&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85031023828&partnerID=8YFLogxK

U2 - 10.1021/acs.chemmater.7b03813

DO - 10.1021/acs.chemmater.7b03813

M3 - Article

AN - SCOPUS:85031023828

VL - 29

SP - 8548

EP - 8554

JO - Chemistry of Materials

JF - Chemistry of Materials

SN - 0897-4756

IS - 19

ER -