Callaghan Innovation Research Papers

Back to Research Papers

TitleOptical properties of CdSe1-xSx nanoparticles
Publication TypeConference Paper
Year of Publication2010
AuthorsRaymond, S.G., Clarke D.J., Janssens S., and Williams G.V.M.
Conference NameProceedings of SPIE - The International Society for Optical Engineering
Date Published2010
KeywordsA-thermal, Absorption measurements, Activation energy, Cadmium alloys, Cadmium compounds, Electrooptical devices, Nanoparticles, Non-radiative recombinations, Optical properties, Optoelectronic devices, Photoluminescence, Photoluminescence lifetime, PL emission energies, PL lifetime, PL measurements, Quantum confinement, quantum yield, sulfur, Sulfur concentrations, Temperature dependent, Temperature independents, Thermal activation, Transition energy
AbstractPhotoluminescence (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→1S e 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. © 2010 Copyright SPIE - The International Society for Optical Engineering.

Back to top