Temperature dependent optical properties of PbS nanocrystals.

Nordin, MN, Li, J, Clowes, SK and Curry, RJ (2012) Temperature dependent optical properties of PbS nanocrystals. Nanotechnology, 23 (27).

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Abstract

A comprehensive study of the optical properties of PbS nanocrystals (NCs) is reported that includes the temperature dependent absorption, photoluminescence (PL) and PL lifetime in the range of 3-300 K. The absorption and PL are found to display different temperature dependent behaviour though both redshift as temperature is reduced. This results in a temperature dependent Stokes shift which increases from ∼75 meV at 300 K with reducing temperature until saturating at ∼130 meV below ∼150 K prior to a small reduction to 125 meV upon cooling from 25 to 3 K. The PL lifetime is found to be single exponential at 3 K with a lifetime of τ(1) = 6.5 μs. Above 3 K biexponential behaviour is observed with the lifetime for each process displaying a different temperature dependence. The Stokes shift is modelled using a three-level rate equation model incorporating temperature dependent parameter values obtained via fitting phenomenological relationships to the observed absorption and PL behaviour. This results in a predicted energy difference between the two emitting states of ∼6 meV which is close to the excitonic exchange energy splitting predicted theoretically for these systems.

Item Type:	Article
Authors :	Name Email ORCID Nordin, MN Li, J Clowes, SK Curry, RJ
Date :	11 July 2012
DOI :	10.1088/0957-4484/23/27/275701
Depositing User :	Symplectic Elements
Date Deposited :	28 Mar 2017 14:08
Last Modified :	31 Oct 2017 14:40
URI:	http://epubs.surrey.ac.uk/id/eprint/712814

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