Hello Sudhir,

To determine the the QY the following things might be helpful:

1. If the chromophores are soluble in ethanol, then measure both sample and ref in ethanol, use of same sample make the calcualtion more easier.

2. overlap the absorption spectrum and find suitable wavelength that posses in both sample and ref.

3. Make five sample ranging from 0.01 to 0.1 Abs: eg 0.02, 0.04, 0.06, 0.08 and 0.1 at that wavelength.

4. Excite both sample and ref for each time at that wavelength as excitation wavelength and record integrated area.

5. Plot and calculate according to the equation.

The attachments might be helpful.

Thanks a lot for reply.

Here, I have attached the absorption spectra of both ref (rhodamine 6g) and sample. The spectra have taken in ethanol and toluene respectively. In ethanol, the QY of rhodamine 6g is 0.95 and lambda excitation wavelength is 488 nm, frequently reported in literature. Excitation wavelength for both dyes would be perfect at 488 nm?

According to your plot, I think the best choise will be the wavelength between 525 - 550 nm. Although I have not varified the result with different excitation wavelength and the results are expected to be similar. Then you can compare with the result for the case of 488 nm. How about the solubility of your sample in ethanol? If not soluble then toluene is ok, just you have consider their refractive index in respective solvent during calculation.

When using different solvents, don't forget to apply the correction for differing refractive indices. The 1971 review article from Demas and Crosby has still all the information you need...

Article Measurement of photoluminescence quantum yields. Review

First of all, I thank to Dr. Friedrich Menges.

I have gone through the mentioned review where I found several corrections should be considered such as

1) Refractive Index Corrections.

2) Reabsorption Corrections.

3) Reemission Corrections.

4) Polarization Corrections.

Apart from these, I would like to know any more additional corrections in emission or absorption spectra are required?

In https://www.nature.com/articles/nprot.2013.087.pdf paper (figure 7), spectral correction in emission spectra has been introduced. But I didn't get how they have done it. This is same as above mentioned correction or some different?

When measuring fluorescence spectra, the raw spectra are always distorted by wavelength-dependent detector sensitivity. You have to correct for this sensitivity to obtain "true spectra". Only for true spectra, the comparison of area under curve between spectra of different shape or from different substances makes sense. As the area under curve is used in quantum yield determination, this is also a requirement. You might check with your spectrometer manufacturer's customer support or study the manual to find out. Some manufacturer's have it automatedly, some as an option and for some you ned to do it yourself...

I am very new in this field, I have no idea about getting the true spectra. What is the suitable procedure for the correction?

Is any software there for correction?

I am using Varian Cary Eclipse Fluorescence Spectrometer. In this Spectrometer, correction is required? I have attached some emission spectra (origin file and image) taken from this Spectrometer, plz, see them.