Tight binding approximation in Nd3+ doped nano ceria prepared via gel combustion method

Neodymium doped nano ceria powder was synthesized through gel combustion route using urea formaldehyde as fuel. The powder was characterized through XRD, TEM and spectrophotometry. Small nanograins consisting of single crystals of around 5–15 nm size (against 10–20 nm as estimated by Scherrer equation) were observed under TEM. Decrease in crystallite size with corresponding lattice expansion follows quamtum confinement effect. The measured band gap ranges from 2.71 to 3.84 eVs. The effect of doping concentration on band gap of ceria nanocrystals along with simultaneous change in lattice parameter has been explained in the light of tight binding approximation.