The effect of intensity of excitation on CdSe/ZnS quantum dots : opportunities in luminescence sensing
Sutter, Jens U. and Birch, David J. S. and Rolinski, Olaf J. (2011) The effect of intensity of excitation on CdSe/ZnS quantum dots : opportunities in luminescence sensing. Applied Physics Letters, 98 (2). 021108. ISSN 0003-6951 (https://doi.org/10.1063/1.3534784)
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We report changes in the photophysical properties of core-shell type CdSe/ZnS quantum dots (QDs) under optical irradiation. QDs either in aqueous solution or immobilized in a silica sol gel matrix have been excited at different wavelengths and fluxes. Illumination of the sample with 140 fs 700 nm Ti:sapphire laser pulses of the peak power of the order of 4 GW/cm(2) caused gradual increase in the luminescence lifetime from an initial value of 3.5 increasing to 4.5 ns and an increase in luminescence intensity by similar to 8%. Using about 16 GW/cm(2) peak power resulted in a shortening of the luminescence lifetime to 3 ns and a decrease in intensity by similar to 75%. Both photobrightening and photodarkening were fully reversible. We discuss the kinetics of photobrightening and photodarkening and investigate the suitability of QDs as luminescence lifetime sensors with tunable parameters.
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Item type: Article ID code: 30188 Dates: DateEvent11 January 2011PublishedSubjects: Science > Physics Department: Faculty of Science > Physics Depositing user: Pure Administrator Date deposited: 15 Nov 2011 16:48 Last modified: 08 Apr 2024 18:56 Related URLs: URI: https://strathprints.strath.ac.uk/id/eprint/30188