Tuning the charge carrier dynamics via interfacial alloying in core/shell CdTe/ZnSe NCs

Maiti, Sourav ; Debnath, Tushar ; Maity, Partha ; Ghosh, Hirendra N. (2015) Tuning the charge carrier dynamics via interfacial alloying in core/shell CdTe/ZnSe NCs Journal of Physical Chemistry C, 120 (3). pp. 1918-1925. ISSN 1932-7447

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Official URL: http://pubs.acs.org/doi/abs/10.1021/acs.jpcc.5b099...

Related URL: http://dx.doi.org/10.1021/acs.jpcc.5b09904


For core/shell semiconducting nanocrystals the interface plays an important role governing the charge carrier dynamics. This work focuses on CdTe/ZnSe spherical core/shell NCs where the optical spectra and charge carrier dynamics can be tuned depending on the synthetic conditions employed. When ZnSe is coated on top of CdTe core at nominal (∼220 °C) reaction temperature the effect of interfacial alloying is less pronounced. Interestingly, as the reaction temperature is sequentially changed between 220 and 280 °C during core/shell synthesis a blue-shifted short-lived (∼10 ns) emission appears accompanied by the normal long-lived (∼36 ns) core/shell emission. This blue-shifted emission has its origin in the interfacial alloyed layer which forms due to ionic diffusion. At elevated temperature (∼280 °C) this blue emission diminishes with an increase in the overall QY for the core/shell emission around 700 nm. Ultrafast transient absorption spectroscopy reveals the interplay of carrier population dynamics in first and higher excitonic states which are subsequently affected by interfacial alloying.

Item Type:Article
Source:Copyright of this article belongs to American Chemical Society.
ID Code:102073
Deposited On:27 Jan 2017 17:16
Last Modified:27 Jan 2017 17:16

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