Issue 47, 2018

Switchable dissociation of excitons bound at strained CdTe/CdS interfaces

Abstract

Charge carrier dynamics of semiconductor nano-heterostructures are determined by band alignment and lattice mismatch of the adjacent materials. However, quantum efficiencies for the separation of excited charge carriers at such an interface are hard to predict and cannot yet be easily controlled. In this work we examine nanorods with a severely strained, axial CdTe/CdS interface using femtosecond transient absorption spectroscopy. We show that charge separation is mitigated by equal contributions of valence band distortion and formation of coulomb pairs across the interface. Left undisturbed such localised excitons relax rapidly via non-radiative recombination channels. By adding a competitive hole acceptor that disrupts the coulomb interaction we overcome the synergetic co-localisation of the carriers and realise charge separation. The thus created long-lived state can be exploited for a broad range of applications such as photocatalysis, water splitting, and switchable nanodevices.

Graphical abstract: Switchable dissociation of excitons bound at strained CdTe/CdS interfaces

Supplementary files

Article information

Article type
Paper
Submitted
30 Sep 2018
Accepted
17 Nov 2018
First published
19 Nov 2018

Nanoscale, 2018,10, 22362-22373

Switchable dissociation of excitons bound at strained CdTe/CdS interfaces

F. Enders, A. Budweg, P. Zeng, J. Lauth, T. A. Smith, D. Brida and K. Boldt, Nanoscale, 2018, 10, 22362 DOI: 10.1039/C8NR07973K

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