Design and synthesis of heterostructured quantum d
Post# of 22456
Posted On: 03/11/2015 10:59:55 AM
Design and synthesis of heterostructured quantum dots with dual emission in the visible and infrared.
ACS Nano 2015 Jan 18;9(1):539-47. Epub 2014 Dec 18.
Qianglu Lin, Nikolay S Makarov, Weon-Kyu Koh, Kirill A Velizhanin, Claudiu M Cirloganu, Hongmei Luo, Victor I Klimov, Jeffrey M Pietryga
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.
Affiliation
Center for Advanced Solar Photophysics, Los Alamos National Laboratory
http://www.pubfacts.com/detail/25427007/Desig...d-infrared
ACS Nano 2015 Jan 18;9(1):539-47. Epub 2014 Dec 18.
Qianglu Lin, Nikolay S Makarov, Weon-Kyu Koh, Kirill A Velizhanin, Claudiu M Cirloganu, Hongmei Luo, Victor I Klimov, Jeffrey M Pietryga
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.
Affiliation
Center for Advanced Solar Photophysics, Los Alamos National Laboratory
http://www.pubfacts.com/detail/25427007/Desig...d-infrared
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