Φx = ΦST (mx / mST) (η2

x /η2

ST )

Where Φ is the quantum yield, m is slope, η is the refractive index of the solvent, ST is the

standard and X is the sample.

Kiran.. you can calculate with the help of Fluorescece.

First of all you need to take the fluorescence of your sample and note the intensity and wavelength.

And then take any one of these( Tryptophan, Quinine sulphate , Fluorescein)as reference and do the fluorescence and note the intensity and wavelength.

you can use the above or below attached file formula to calculate.

This is how I did the calculation on my recent published work:

Fluorescence quantum yield (QY) of CDs was determined by comparing

the integrated photoluminescence (PL) intensities with quinine

sulfate as the standard (QY of 54%) in 0.1M H2SO4. The absorbance of

the CDs in aqueous media and the reference sample was kept below 0.10 at 320 nm to avoid inner filter effects. The QY of the samples were

estimated from:

QY (X) = QYs tan dard (A A )(F F )(ƞ ƞ )

standard 2

x

x

standard standard where the

subscript “x” and “standard” refer to CDs and quinine sulfate, respectively;

A is absorbance at the excitation wavelength; F is integrated

emission under fluorescence spectrum; ƞ is the refractive index of the

solvent.