Thank you, Gert, up to now I found this Allura red as most suitable sample for my setup. But it is not "perfect"=) because they measure here lifetimes for maximum wavelength of 750 nm. And my detector is sensitive only in a range 900-1700 nm. That means I will asume without knowing for sure that Allura red has same short lifetime. (In the paper they show slight increase in lifetime for longer wavelength 96 to 102 ps for 550 to 759 nm but who knows what happens from 750 to 900).

I want to try it, but maybe there is something else I can use with known lifetimes.

Thank you, that looks not easy but interesting) will read the articles tomorrow.

I am looking on the decay of Germanium quantum dots in silicon photoluminescence. I excite them with 445 nm laser and they emit at 1200-1500 nm.

The decay time is short so I cannot neglect the IRF.

And the detector I have is not sensitive to visible light so unfortunately I cannot measure scattered laser light.

Yes, they are embedded in silicon layer (were grown by molecular beam epitaxy) so actually silicon is absorbing visible light and transfer energy to Ge QDs. 

At least spectra for 445 and 532 nm excitation wavelength look similar.