Dear Ambreen,

It is not necessary that PL samples require liquid sample only. I am working on inorganic luminescent materials and they are in powder form, we have powder sample holder and I am easily getting PL. If your samples are in powder form, you may use powder sample holder for PL measurements.

Thanks Rupesh and Mathew! Please add that how to increase the intensity of emission and to get even PL spectrum without noise. Does the amount of fluorescent material in suspension matters ? I fact there is no sample holder available for solids.

For the purpose of photoluminescence you can dissolve your sample in water by  indirect method. Dissolve your sample in a solvent which in which it is highly soluble (say methanol, DMSO). Then take an aliquot (20 microlit) of the concentrated solution and add this to 2 ml water. In most of the case a transparent solution is obtained.

Powder sample holders are available. You can easily get powder sample holder or you can design your own powder sample holder. You may use your sample sandwiched between two quartz plate. Use transparent glue tape to hold the quartz plate. I have use this design and It works.