Abstract
The unique optical properties exhibited by visible emitting core/shell quantum dots with especially thick shells are the focus of widespread study, but have yet to be realized in infrared (IR)-active nanostructures. We apply an effective-mass model to identify PbSe/CdSe core/shell quantum dots as a promising system for achieving this goal. We then synthesize colloidal PbSe/CdSe quantum dots with shell thicknesses of up to 4 nm that exhibit unusually slow hole intraband relaxation from shell to core states, as evidenced by the emergence of dual emission, i.e., IR photoluminescence from the PbSe core observed simultaneously with visible emission from the CdSe shell. In addition to the large shell thickness, the development of slowed intraband relaxation is facilitated by the existence of a sharp core-shell interface without discernible alloying. Growth of thick shells without interfacial alloying or incidental formation of homogeneous CdSe nanocrystals was accomplished using insights attained via a systematic study of the dynamics of the cation-exchange synthesis of both PbSe/CdSe and the related system PbS/CdS. Finally, we show that the efficiency of the visible photoluminescence can be greatly enhanced by inorganic passivation.
| Original language | English |
|---|---|
| Pages (from-to) | 539-547 |
| Number of pages | 9 |
| Journal | ACS Nano |
| Volume | 9 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - Jan 27 2015 |
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Keywords
- cation exchange
- core/shell nanocrystal
- dual emission
- effective-mass model
- quantum dots
- vacancy formation
ASJC Scopus subject areas
- Engineering(all)
- Materials Science(all)
- Physics and Astronomy(all)
Cite this
Design and synthesis of heterostructured quantum dots with dual emission in the visible and infrared. / Lin, Qianglu; Makarov, Nikolay S.; Koh, Weon Kyu; Velizhanin, Kirill A.; Cirloganu, Claudiu M.; Luo, Hongmei; Klimov, Victor I; Pietryga, Jeffrey M.
In: ACS Nano, Vol. 9, No. 1, 27.01.2015, p. 539-547.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Design and synthesis of heterostructured quantum dots with dual emission in the visible and infrared
AU - Lin, Qianglu
AU - Makarov, Nikolay S.
AU - Koh, Weon Kyu
AU - Velizhanin, Kirill A.
AU - Cirloganu, Claudiu M.
AU - Luo, Hongmei
AU - Klimov, Victor I
AU - Pietryga, Jeffrey M.
PY - 2015/1/27
Y1 - 2015/1/27
N2 - The unique optical properties exhibited by visible emitting core/shell quantum dots with especially thick shells are the focus of widespread study, but have yet to be realized in infrared (IR)-active nanostructures. We apply an effective-mass model to identify PbSe/CdSe core/shell quantum dots as a promising system for achieving this goal. We then synthesize colloidal PbSe/CdSe quantum dots with shell thicknesses of up to 4 nm that exhibit unusually slow hole intraband relaxation from shell to core states, as evidenced by the emergence of dual emission, i.e., IR photoluminescence from the PbSe core observed simultaneously with visible emission from the CdSe shell. In addition to the large shell thickness, the development of slowed intraband relaxation is facilitated by the existence of a sharp core-shell interface without discernible alloying. Growth of thick shells without interfacial alloying or incidental formation of homogeneous CdSe nanocrystals was accomplished using insights attained via a systematic study of the dynamics of the cation-exchange synthesis of both PbSe/CdSe and the related system PbS/CdS. Finally, we show that the efficiency of the visible photoluminescence can be greatly enhanced by inorganic passivation.
AB - The unique optical properties exhibited by visible emitting core/shell quantum dots with especially thick shells are the focus of widespread study, but have yet to be realized in infrared (IR)-active nanostructures. We apply an effective-mass model to identify PbSe/CdSe core/shell quantum dots as a promising system for achieving this goal. We then synthesize colloidal PbSe/CdSe quantum dots with shell thicknesses of up to 4 nm that exhibit unusually slow hole intraband relaxation from shell to core states, as evidenced by the emergence of dual emission, i.e., IR photoluminescence from the PbSe core observed simultaneously with visible emission from the CdSe shell. In addition to the large shell thickness, the development of slowed intraband relaxation is facilitated by the existence of a sharp core-shell interface without discernible alloying. Growth of thick shells without interfacial alloying or incidental formation of homogeneous CdSe nanocrystals was accomplished using insights attained via a systematic study of the dynamics of the cation-exchange synthesis of both PbSe/CdSe and the related system PbS/CdS. Finally, we show that the efficiency of the visible photoluminescence can be greatly enhanced by inorganic passivation.
KW - cation exchange
KW - core/shell nanocrystal
KW - dual emission
KW - effective-mass model
KW - quantum dots
KW - vacancy formation
UR - http://www.scopus.com/inward/record.url?scp=84921768901&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84921768901&partnerID=8YFLogxK
U2 - 10.1021/nn505793y
DO - 10.1021/nn505793y
M3 - Article
AN - SCOPUS:84921768901
VL - 9
SP - 539
EP - 547
JO - ACS Nano
JF - ACS Nano
SN - 1936-0851
IS - 1
ER -