I want measuring the PL decay time profile of a sample by LS50-B FLUORESCENCE SPECTROMETER(Perkin elmer ) . but I do not know how to measure it.Has anyone done this kind of experiment? Please suggest what I have to do.
The instrument you use is best suited for measuring the steady state fluorescence and it is not time resolved. If it is the standard LS50B, it uses a pulsed lamp to synchronize the detection system to the repetition rate of the lamp in order to mitigate ambient light. But you can not measure the fluorescence emission decay curve with it.
You need a plulsed laser source and a photodetector that is capable of photon countinng and a time correlated photon counting card to measure emission decay curves. If the emission decays slow enough (like the emission from some rare earth elements, then you just need a pulsed LED or laser diode and a fast Photomultiplier tube and a fast oscilloscope (300MHz would be ideal, but you can measure tens of microsecond scale decays with a 100 MHZ oscilloscope).
I have never used this model but I have used Cary Eclipse fluorimeter where it is possible to measure long lifetime decay (phosphorescence, rare earth metal) in single shot. If your sample gives normal fluorescence you have to use TCSPC like system (already mentioned by Jose Hodak). What I saw online is that you can measure phosphorescence in LS-50B. If you are able to vary the delay time in phosphorescence mode then you can measure the decay from steady state intensity. The delay time vs integrated intensity plot will be the decay profile. Please see the attached decay of Tb3+ I have measured in Cary Eclipse using this method
Tuhin, please can you elaborate the use of Cary eclipse to find decay time profile of any fluorescent sample
@Anupma. It is not possible to measure lifetime of fluorescent sample in Cary Eclipse. In order to measure a decay in this instrument the lifetime should be more than 200 microsecond. The pulsed xenon lamp has a time width in excess of 10 microsecond.
Thank you for considering my question.
@Tuhin Khan. can you explain me how do I turn off the Xenon discharge lamp in phosphorescent mode for the entire test time and turn on only in the first moment?
I have no experience in that particular model. So I cannot help you in this case.
yes you can by a Manual method! using
LS50-B
you mesured emission spectrat at difrent times and you plots the intensity of the maxium =f(t) you will had you decy courve!
see Effect of pH value on structural and photoluminescence properties of Tb3þ -doped Lu2O3 nanopowders synthesized by solegel route
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