Hi. enclose a short link, on how to perform QY experiments. In order to choose the right reference fluorophore, first of all the absorption properties are important, since you assume, that both fluorophores absorb in the same spectral range, the same amount of photons - and hence you can reference their emitted photons collected in a given spectral range. So in this respect, also the emission window is important...

In case that your sample emits around 780nm with an excitation around 530?nm - you could go for s.th like styryl6. (second link)

http://www.horiba.com/fileadmin/uploads/Scientific/Documents/Fluorescence/quantumyieldstrad.pdf

http://www.chem.ucla.edu/~craigim/pdfmanuals/catalogs/Lamdachrome-laser-dyes.pdf

Hi. enclose a short link, on how to perform QY experiments. In order to choose the right reference fluorophore, first of all the absorption properties are important, since you assume, that both fluorophores absorb in the same spectral range, the same amount of photons - and hence you can reference their emitted photons collected in a given spectral range. So in this respect, also the emission window is important...

In case that your sample emits around 780nm with an excitation around 530?nm - you could go for s.th like styryl6. (second link)

http://www.horiba.com/fileadmin/uploads/Scientific/Documents/Fluorescence/quantumyieldstrad.pdf

http://www.chem.ucla.edu/~craigim/pdfmanuals/catalogs/Lamdachrome-laser-dyes.pdf

Please read the attached material

Good Luck

Thanks for your suggestions and references i will refer and clarify my doubts.