It can be seen that these nanoparticles exhibit two distinct photoluminescence bands,
one with the peak position at 500 nm and the other with the peak position at 580 nm.
The photoluminescence band with the peak at 500 nm gets converted to another band with the peak at 580 nm
upon increase in the excitation wavelength from 380 nm to 480 nm under identical conditions.
This clearly indicates that with decrease in the excitation photon energy the red shifted photoluminescence band dominates. The present observation could not be correlated to the size distribution of the CdSe
nanoparticles, as the size of the primary nanoparticles was about 3 nm without much variation.
It is to be mentioned here that, this observation is quite different from the earlier study reported by Chandrasekharan and Kamat