you can use the method of integrating sphere. I used it for thins films deposited on quartz. probably you can do the same by sandwiching the powder between two substrates or somehow sticking it on the substrate.

http://onlinelibrary.wiley.com/doi/10.1002/adma.19970090308/abstract

Here is a video showing how to do this:

https://www.ncbi.nlm.nih.gov/pubmed/22617474

Thank you Andrea and Adam...

Presently am not in a position to use integrated sphere. we have one but its an attachment for measuring UV- visible absorption measurement of powder samples.

I can measure the emission , and absorption but cant use integrated sphere ..........

Any other option.....

The only other way I know is in solution using a reference dye. You can find the procedure quite easily.

Check if you can dissolve your sample in some solvent..

You can calculate fluorescence quantum yield by another way. Measure fluorescence lifetime and use the formula

Fluorescence quantum yield = Radiative rate constant x fluorescence lifetime

But this requires that you know the radiative rate constant. This has to be measured by other ways. You can see my publication on how to measure the radiative rate constant.