IS IT CORRECT TO Use The absorbance of aggregate solution if the absorbance value is significantly changed/increased due to leveling off tail/mid scattering.
you can change the exciation and emission slits. increase the emission slit and decrease the excitation slit.
Thanks for your suggestion Dr. Yang but changing the slit width doesn't remove the effect of leveling off tails in UV spectrum which hamper the calculation of actual absorbance of sample.
Hi Gopal Singh:
UV(200-400nm) is very weak in xenon lamp. By setting up the standard, the error of UV range is large. So, 300nm blazed grating is needed, which can enhance the UV intensity and decrease error . In integrating sphere, the special coating reflecting 200-400nm is needed. you know, BaSO4 coating has absorption in 200-400nm. only you know your device, you can obtain the desired data.
Sorry for my late response. My problem is related to the scattering of incident radiation due to aggregates (nanoparticles) also known as Mie scattering, which cause leveling off tail. It cause high apparent absorption so it becomes difficult to measure actual absorbance of the material.
Hi Gopal Singh
Do not worry about the scattering of nanparticles, which is gentle downslope and can be ruled out as backland.
I would subtract the scattering part like a baseline from the absorbance spectrum. This gives you the "true" absorbance spectrum. As the emission is proportional to the fraction of really absorbed light, you'll be able to calculate real quantum yields.
I just implemented this kind of absorbance baseline subtraction into Spekwin32, an optical spectroscopy software maintained by me. the algorithm allows to model scattering for different scattering types, asit is proportional to the wavelength to different powers, like squared, cubic or even fourth power depending on scattering (Rayleigh, Mie, ...) Could provide you a preview version, just let me know...
This is very interesting Dr Menges. I am very much interested to know about how you are able to do it. Thanks for your response.
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