On the photo-luminescence properties of sol–gel derived undoped and Dy3+ ion doped nanocrystalline Scheelite type AMoO4 (A = Ca, Sr and Ba)

Nanocrystalline Scheelite type Dy doped AMoO4 [where A = Ba, Sr and Ca] samples were prepared by acrylamide assisted sol–gel process and characterized by XRD, FT-Raman, FTIR, SEM and photoluminescence (PL). PL of undoped sample shows blue/green emission in CaMoO4 and SrMoO4 but multicolour visible emission leading to near white light in BaMoO4 nanoparticles; the origin of which is explained. It was observed that on doping 0.5 mol% of Dy3+ in molybdate samples complete energy transfer takes place in case of SrMoO4 and BaMoO4, but host contributed substantially in Dy doped BaMoO4 sample, resulting in biexponential decay. It was also observed that symmetry around Dy3+ decreases as the size of alkaline earth ion increases. Due to combined blue, yellow and red colour emission in dysprosium doped sample; all samples showed near white light emission under UV and near UV excitation.