i want to know the experimental techniques and form of samples...powder form or solution form or glass form ...?
For taking Photoluminescence (PL) spectra of any material one must know its absorption bands. Therefore, one should first take UV-visible absorption or reflectance spectra depending on whether the material is transparent or opaque and whether it is a single crystal/glass or powder. Generally, absorption spectra of the transparent single crystal/glass could be taken. In cases of opaque or powder material diffused reflectance spectra is taken. After identifying the absorption bands, the PL excitation spectra or emission spectra could be taken on a fluorescence spectrophotometer. However, the spectrophotometer should have a solid sample attachment with powder sample holder. The solid sample attachment is generally a vertical platform (plane) at 45 degrees to the incident beam so that the emitted light could be reflected at 90 degrees and scanned by the emission monochromator. The incident beam wavelength is generally set as the excitation wavelength. Excitation spectra, is taken for a particular emission wavelength. Excitation spectra generally resembles with the absorption spectra. If the absorption spectra is not known, the excitation spectra still could be found by some permutation and combinations of the excitation and emission spectra.
respected sir....we made borate glasses..then we grinded our glasses and obtained in powder form. after that we observed absorption spectra by uv/vis spectroscopy ( diffuse reflectance spectra of our powder samples). the procedure which is taken by me ...is it right ??
Dear Sumit, your procedure is correct. But it won't give you PL emission/excitation spectra. You will have to take it on a Fluorescence Spectrophotometer.
sir for fluorescence , the sample should be in which form ? powder form of glass or glass form . sir i want to meet you and learn the many things. i will be highly obliged.
thanks
You can do the PL or fluorescence with powder sample as well as glass form
you can record PL spectra for both glasses and powder froms, but it better to go with solid samples because in my point of view, in power form, the intensities of the bands will reduce up to 95%.
PL excitation spectra or emission spectra could be taken on a fluorescence spectrophotometer.
First the excitation (EX) spectra were recorded by setting the emission wavelength at the zero order and keeping other parameters as specified in the manual. The excitation bands (EX) were identified from these spectra and the emission (EM) spectra were scanned for identified excitation wavelengths. This was necessary to know approximate nature of EX and EM spectra. While doing so the direct scattered light may superimpose on the EX spectrum. So it is necessary to select a particular band in the emission for scanning the excitation. Therefore for proper excitation wavelengths, EM was set at the position as identified from the earlier emission spectrum. Again the same procedure was followed for identifying the proper EX positions and EM was recorded for each EX band separately.
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