“…In recent years some attempt have been performed for the preparation of RE ion doped cerium oxide by various techniques such as pyrolysis [4], solvothermal synthesis [2,14], sonochemical synthesis [15], the two-stage co-precipitation process [16,17], sol-gel process [1,8], solid-state ceramic reactions [18], microwave irradiation [19] and so on [14][15][16][17][18][19][20][21][22]. Relatively few reports are based on structural and optical properties of RE ions doped CeO 2 [1,[15][16][17][18][19].…”