Dear Snahasish Bhowmik

I personally never used FTIR to analyze perovskites, but the following procedure might be a good first insight:

An FTIR analysis will give you different peak-shaped signals that are related to different chemical functional groups. To relate the signals with the groups, there are tables available online. That way, you can estimate and understand the chemical structure of your sample. When the sample is a solid, normally the procedure is to grind the solid (sometimes this solid is mixed with anhydrous KBr, which is transparent to the IR wavelengths) and make an IR light to pass through the sample. Normally, you sweep at different wavelenghts in the IR region while measuring the transmittance (or absorption) of the sample. The idea of using KBr is just to avoid the saturation of the spectra, and make it easier to read, but there is a technique called ATR-FTIR for which this KBr approach is not required. The use of this technique depends mainly on the availability of the equipment you have to use it.

Maybe some article like this one can be useful to give you insights on how to design your experiments: Article Highly Efficient Perovskite Nanocrystal Light-Emitting Diode...

Hope it helps!

Thank you.

rather than FT-IR, better use Raman Spectroscopy. As the vibration metal-oxide are at lower wave length. You can observer more there and correlate the data with the XRD