Charge separation by indirect bandgap transitions in CdS/ZnSe type-II core/shell quantum dots

Verma, Sandeep ; Kaniyankandy, Sreejith ; Ghosh, Hirendra N. (2013) Charge separation by indirect bandgap transitions in CdS/ZnSe type-II core/shell quantum dots Journal of Physical Chemistry C, 117 (21). pp. 10901-10908. ISSN 1932-7447

Full text not available from this repository.

Official URL: http://pubs.acs.org/doi/abs/10.1021/jp400014j

Related URL: http://dx.doi.org/10.1021/jp400014j

Abstract

Femtosecond time-resolved absorption and picosecond time-resolved emission studies have been carried out to study the indirect type exciton of CdS/ZnSe core/shell quantum dots (QDs). The CdS/ZnSe core/shell QD samples are synthesized with increasing thickness of ZnSe shell on CdS core QDs. In these CdS/ZnSe core/shell samples, a new energy band lower than the energy gap of both the CdS core and ZnSe shell has been observed and attributed to indirect bandgap transitions from the valence band of the ZnSe shell to the conduction band of the CdS core. The transient PL studies have revealed that the indirect type exciton, e(CdS)/h(ZnSe) due to photoexcitation of this low-energy band, endures less carrier trapping than selective excitation of the CdS core and charge transfer in the staggered photoexcited state. Femtosecond transient absorption studies have revealed that carrier trapping is as fast as 100 fs and interfacial charge recombination slows down with increasing ZnSe shell thickness on the CdS QD in CdS/ZnSe core/shell QDs.

Item Type:Article
Source:Copyright of this article belongs to American Chemical Society.
ID Code:101764
Deposited On:01 Feb 2017 10:32
Last Modified:01 Feb 2017 10:32

Repository Staff Only: item control page