If PLQY calculating by using as a standard reference. is it essential to match both absorption and emission spectra of compound with standard? or any one should match? or only emission wavelength should match? please give explanation and reference also.
Assuming that you are measuring the fluorescence quantum yield in solutions by using a standard reference. You are indeed using a reference standard as i can see.
In the formula, there are terms associated with refractive index of the solvent, absorbance of the solution and area under the emission spectrum.
For emission, it is better if the wavelength range of sample and reference matches because your instrument response (e.g. detector sensitivity etc) to different wavelengths may not be the same.
For absorbance, it is not essential since it is only measured at a single wavelength by using the formula A=-log(I/I0). So even if the wavelengths of the sample and reference differ, it does not matter because it is the negative log of ratio of intensities.Ratio of the intensities takes care of all the instrumental factors which change with wavelength.
In fact, it does matter! Your answer right is right for the absorbance part. But the excitation intensity of the fluorescence spectrometer is strongly wavelength dependent, you have to correct for this differing energies in order to get correct quantum yields.
Just to add more details, you have to convert the x-axis of fluorescent emission spectra to energy scale from wavelength scale, for comparison and use this spectra for calculation of area under the peak.
thank you very much for the clarification. and in my case, sample and reference are showing same range of emission. but in the absorbence there is no peak is matching. so what shell i do for that.
you might have a look at previous ResearchGate discussions, where you can also find links to helpful papers:
https://www.researchgate.net/post/Whats_wrong_with_my_quantum_yield_measurement
https://www.researchgate.net/post/What_is_the_linear_range_of_Quinine_Sulphate_Quantum_Yield
https://www.researchgate.net/post/Can_anyone_help_with_quantum_yield_measure_and_standard_sample_choice
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