I worked on cellulose. My understanding is that crystallinity is related to the organization of polymeres. Hydrogen bonds make cellulose very crystalline. It means the more crystallinity, less is the space between polymeres. In my case; data showed that the chemical reaction with acid was slow when the crystallinity is high. It could be the same for luminescence.

Thank you, Sir, for your suggestions.

However, I work on luminescence studies of polycrystalline materials. I observed low luminescence from poor crystalline material. I do not know how to account that.

Regards

Sitakanta Panda.

Dear Sitakanta,

In general, luminescence efficiency is directly proportional to crystallinity in case of phosphor materials. Generally, when some luminescence activators are doped into a host to develop a phosphor, various kind of defects are introduced in the lattice. In most of the cases these defects are: vacancy due to charge imbalance, volume defect due to different ionic radii of host and dopant atoms, different surface states etc. In order to achieve strong luminescence, it is necessary to reduce these defects as minimum as possible. Charge compensation by adding extra co-activator, is a strategy that can solve the charge imbalance problem. You can have a look into the following papers to get a clear idea.

1. https://pubs.rsc.org/en/content/articlehtml/2013/dt/c3dt51411k

2. https://pubs.acs.org/doi/abs/10.1021/acs.jpcc.5b03500

3. https://pubs.acs.org/doi/abs/10.1021/acsomega.7b01525

Best regards,

SS

Dear Subhajit,

Thank you very much. It is useful.