Paper
15 November 2010 Optical properties of CdSe1-xSx nanoparticles
S. G. Raymond, D. Clarke, S. Janssens, G. V. M. Williams
Author Affiliations +
Abstract
Photoluminescence (PL) and absorption measurements have been made on CdSe1-xSx nanoparticles with x=0.69 to x=1 using a process that should lead a graded sulfur fraction where the sulfur fraction is lowest in the core. There is a systematic increase in the 1S3/2→1Se transition energy and the 1Se→1S3/2 PL emission energy that can be attributed to an increasing sulfur concentration. The quantum yield is ~30% for 0.69≤x≤0.83. It decreases to 0.7% for higher values as x approaches 1. The higher quantum yields for x≤0.83 may be due to the graded sulfur concentration that leads to a thermal barrier that reduces non-radiative recombination at the surface. Temperature dependent PL measurements on a x=0.83 sample are consistent with two PL lifetimes where the longer one (~30 ns) is nearly temperature independent and could arise from a fraction of the nanoparticles having a lower concentration of non-radiative recombination sites. The shorter component can be accounted for by thermal activation to surface non-radiative recombination sites with an activation energy of 9.6 meV.
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S. G. Raymond, D. Clarke, S. Janssens, and G. V. M. Williams "Optical properties of CdSe1-xSx nanoparticles", Proc. SPIE 7847, Optoelectronic Devices and Integration III, 784704 (15 November 2010); https://doi.org/10.1117/12.870407
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KEYWORDS
Nanoparticles

Sulfur

Quantum efficiency

Temperature metrology

Polymethylmethacrylate

Luminescence

Absorbance

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