This peak implies the band gap, 2.9, 2.5 and 2.3 eV. The band gap energy decrease, the dielectric constant is increased, recombination rate decrease. This compound is suitable for opto-electronic device.

Thank you sir Nurul Islam

Dear Singh,

I suggest you for looking for any possible defects, mainly, on the nano material surfaces. The possible defects might induce the emission peak in the bandgap area.

Furthermore, I do not think that the peaks can be assumed as (fundamental) bandgaps. Additionally, the excitonic states at 350 nm usually screen the transition from HOMO to LUMO, as the fundamental bandgap.

Regards,

S. Muhammady