I know that gold nanoparticles are actually fluorescent but the efficiency is terribly low. But I think I got some weird signals from a regular fluorometer.
AuNP absorbs at 520 nm, and it can have several emission peaks supposed at [x, y, z...] nm. I cant see these emissions by naked eyes but only by the PMT. The thing is when I tuned the excitation from 520 to 530 nm, all the emission peaks also shifted for 10 nm [x+10. y+10, z+10]
same phenomena were observed in all kinds of nanoparticles. I have tried Au, Ag, CuO, Fe2O3, and some core-shells. And all the emission peaks were at same wavelengths by same excitation light.
The peaks were not observed when I apply air, water in the sample holder
Is this some kind of Raman scattering? intensities are concentration dependent btw
Have a look
Physical Properties of Different Gold Nanoparticles: Ultraviolet-Visible
and Fluorescence Measurements
J Nanomed Nanotechol 2012, 3:3
Have a look
Physical Properties of Different Gold Nanoparticles: Ultraviolet-Visible
and Fluorescence Measurements
J Nanomed Nanotechol 2012, 3:3
Thanks for sharing the paper, but in my case, i observe the peaks at same wavelengths for all kinds of nanoparticles. In the paper, it says `recombination of an electron formed and occupied sp band with the hole resulting in photon emission.` I dont think all nanoparticles have exactly same band gaps. but glad to see someone also notice the weird signals found in fluorometer...
Try to use a long-pass filter to suppress the scattered light from the sample (put it after the sample). You will see - if the signal disappears - it means that you had not a real signal, but just scattered light reaching the detector.
Thanks, i tried with filters today, peaks disappeared. But dont know why there are still so many papers about the fluorescence of gold nanoparticles or the confocol fluorescence images?
Dear all,
I showed increasing of absorbance when increasing magnetic field (presence of magnetic field during laser ablation) of Au-Ag alloy .
what your opinion in this behavior ? why?
The increased absorbance was due to the enlarged size of gold nanoparticle. the extinction coefficient is affected by size of NP. Normally, larger size gives higher scattering and light absorbing cross section, and also bathothermic of absorbance peak.
Since the magneto-optical interaction in NP has been seen in several papers, you probably can try to elucidate why the NPs were melting more efficient under magnetic field. Try to google the ~Faraday rotation~ may help...
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