I have synthesized naphthaldehyde based fluorescent organic molecule and which was further subject to prepare organic nanoparticles by reprecipitation method in an aqueous solution. I observed single little broad emission band for compound in organic solvent, however, red shifted (bathochromically, of about 10-20 nm) sharp bands observed for nanostructured in aqueous suspension. Why this happens; is it possible to have a sharp bands in emission spectrum of nano particles than its broad band emission of parent compound.
Hi Prasad.
Bathochromic shift can occur because of increase in the solvent polarity, double bond conjugation of organic molecule and also decreasing size of nanoparticles (happened in your case). For your case, it is probable energy gap between pi bonding and pi antibonding of the smaller size of organic nanoparticles will be lower than that of the bigger size of the associated particles.
Wibawa sir,
Yes, offcourse. I agree with your valuable suggestion and opinion. But i would like to know that why, nanostructured spectrum have an sharp structured two bands in emission spectrum rather to have an broad band.
Thank you sir for valuable answer in the same
if the wave function is confined In an infinite space, the bondary condition will be very important for the solution of schrondinger function. In one period of de broglie, ther will be a great difference of dielectric constant. Thus, the solution for schrondinger will be fewer as comparing with finite space (bulk materials).
It is also possible that by your experiment to eliminate the cross-relaxation process and as a consequence to minimize surface quenching effects and to increase the overall luminescence efficiency.
Still the reason behind the structured band in emission spectra is not clear to me.I also want to know the origin of structured band as I've observed it in many aromatic amino acid.
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