Depends how you measured the band gap. But generally if the PL is from band-to-band transitions it should shift as the bandgap shifts.

The energy of PL levels in the gap depends on many factors. They may be due to defects or impurities. If it is impurities, the energy levels will be defined by the interaction with the host material or elements of the host material. You need to figure out the origin of PL in your material, and after that answer will be more obvious.

There is a slight redshift in the overall peak but after the deconvolution of peaks, the peak corresponding to Near Band Gap Emission(The peak with the lowest wavelength) shows a blue shift.

Such trends have been reported in papers but don't give any explanation.

Sequinel, T., I. G. Garcia, S. M. Tebcherani, E. T. Kubaski, L. H. Oliveira, M. Siu Li, Elson Longo, and José Arana Varela. "Red shift and higher photoluminescence emission of CCTO thin films undergoing pressure treatment." Journal of alloys and compounds 583 (2014): 488-491.

Dear Sreerag Kaliveetil ,

If the excited electrons are transferred from the minimum of the conduction band to the top of the valence band and the bandgap decreases then the emitted photon energy will be definitely decrease by the same amount. That is red shit will definitely occur.

So, you have to review the measurements of the energy gap.

The optical bandgap differ with the method of measurement whether absorption or emission method, and with the charge carrier degeneracy of the material.

The paper in the link may be useful to you: Article A New and Simple Model for Plasma and Doping induced Band Ga...

Best wishes

Simulation result reveals that redshift is obtained beneath relationship between PL intensity ratio and energy shift were performed. S. Oktyabrsky, “Nanoindentation and near-field spectroscopy of single semiconductor.However, a large field is necessary to reduce fine structure splitting (FSS) to zero