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Abstract
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.
Original language | English |
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Article number | 021108 |
Number of pages | 3 |
Journal | Applied Physics Letters |
Volume | 98 |
Issue number | 2 |
DOIs | |
Publication status | Published - 11 Jan 2011 |
Keywords
- live cells
- in-vivo
- nanoparticles
- anisotropy
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Dive into the research topics of 'The effect of intensity of excitation on CdSe/ZnS quantum dots: opportunities in luminescence sensing'. Together they form a unique fingerprint.Projects
- 2 Finished
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NMS: EPSRC Science and Innovation Nanometrology for Molecular Science, Medicine and Manufacture
Birch, D. (Principal Investigator), Dawson, M. (Co-investigator), Faulds, K. (Co-investigator), Girkin, J. (Co-investigator), Graham, D. (Co-investigator), Martin, R. (Co-investigator), O'Donnell, K. (Co-investigator), Rolinski, O. (Co-investigator), Smith, W. (Co-investigator) & Wynne, K. (Co-investigator)
Scottish Funding Council SFC, EPSRC (Engineering and Physical Sciences Research Council)
1/08/08 → 31/01/12
Project: Research
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Yocto: YOCTOMOLE FLUORESCENCE SENSING OF SINGLE METAL IONS
Rolinski, O. (Principal Investigator) & Birch, D. (Co-investigator)
EPSRC (Engineering and Physical Sciences Research Council)
1/10/06 → 31/08/10
Project: Research