Bilayer stabilized Ln super(3+)-doped CaMoO sub(4) nanocrystals with high luminescence quantum efficiency and photocatalytic properties

In this article, we discuss the microwave synthesis of sodium dodecyl sulphate (SDS) stabilized Ln super(3+)-doped CaMoO sub(4) nanocrystals (Ln super(3+) = Eu super(3+), Er super(3+)/Yb super(3+)). The nanocrystals are quite monodispersed with an average size close to 100 nm. FTIR and TGA analyses suggest strong binding of the SDS molecules to the CaMoO sub(4) nanocrystals surface. The high dispersibility of the nanocrystals in water implies that SDS stabilizes the nanocrystals as a bilayer structure. The SDS coating also assists in the easy dispersion of the nanocrystals in toluene without any additional surface chemistry. The Eu super(3+) ions doped in the CaMoO sub(4) nanocrystals display very strong red luminescence with a quantum yield close to 40%. Under 980 nm excitation, Er super(3+)/Yb super(3+)-dop ed CaMoO sub(4) nanocrystals display Er super(3+) emissions at 550 and 650 nm. In addition, interestingly, a NIR peak at around 833 nm is observed, which occurred viaa three photon process. Furthermore, the CaMoO sub(4) nanocrystals exhibit photocatalytic activity which is studied through the degradation of Rhodamine B (RhB) dye in neutral conditions. The RhB dye is significantly degraded by similar to 80% under UV illumination within 4 h and the rate of degradation is comparable to that observed for well known ZnO nanoparticles. The high luminescence quantum efficiency and strong photocatalytic activity of the Ln super(3+)-doped CaMoO sub(4) nanocrystals make them a potential material for dual applications such as bio-imaging and photocatalysis.