Shell thickness matters! Energy transfer and rectification study of Au/ZnO core/shell nanoparticles
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Date
2016
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Academic Press Inc.
Abstract
In the present study we report the influence of shell thickness on fluorescence resonance energy transfer between Au/ZnO core-shell nanoparticles and Rhodamine 6G dye by steady-state and time-resolved spectroscopy and rectification behaviours. Au/ZnO core-shell nanoparticles with different shell thickness were synthesized in aqueous solution by chemically depositing zinc oxide on gold nanoparticles surface. A pronounced effect on the photoluminescence (PL) intensity and shortening of the decay time of the dye in presence of Au/ZnO core-shell nanoparticles is observed. The calculated energy transfer efficiencies from dye to Au/ZnO are 62.5%, 79.2%, 53.6% and 46.7% for 1.5 nm, 3 nm, 5 nm and 8 nm thickness of shell, respectively. Using FRET process, the calculated distances (r) are 117.8, 113.2 ? 129.9 ? and 136.7 ? for 1.5 nm, 3 nm, 5 nm and 8 nm thick Au/ZnO core-shell nanoparticles, respectively. The distances (d) between the donor and acceptor are 71.0, 57.8, 76.2 and 81.6 ? for 1.5 nm, 3 nm, 5 nm and 8 nm thick core-shell Au/ZnO nanoparticles, respectively, using the efficiency of surface energy transfer (SET). The current-voltage (I-V) curve of hybrid Au/ZnO clearly exhibits a rectifying nature and represents the n-type Schottky diode characteristics with a typical turn-on voltage of between 0.6 and 1.3 V. It was found that the rectifying ratio increases from 20 to 90 with decreasing the thickness of the shell from 5 nm to 3 nm and with shell thickness of 8 nm, electrical transport through the core-shell is similar to what is observed with pure ZnO samples nanoparticles. The results indicated that the Au/ZnO core-shell nanoparticles with an average shell thickness of 3 nm exhibited the maximum energy transfer efficiencies (79.2%) and rectification (rectifying ratio 90). ? 2016
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Keywords
Dyeing, Energy transfer, Fluorescence, Gold, Laser spectroscopy, Nanoparticles, Schottky barrier diodes, Solutions, Spectroscopy, Synthesis (chemical), Zinc oxide, Core-shell nanoparticles, Energy transfer efficiency, Fluorescence resonance energy transfer, FRET, Photoluminescence intensities, Rectification, Shell nanoparticles, Time-resolved spectroscopy, Shells (structures), gold nanoparticle, nanoshell, rhodamine 6G, zinc oxide nanoparticle, aqueous solution diode, electric potentia
Citation
Haldar, K. K., & Sen, T. (2016). Shell thickness matters! Energy transfer and rectification study of Au/ZnO core/shell nanoparticles. Journal of Colloid and Interface Science, 484, 263-269. doi: 10.1016/j.jcis.2016.09.006