Enhanced upconversion fluorescence and altered particle size of β-NaGdF 4 :Yb 3+ /Er 3+ nanocrystals by codoping with Mo 3+ ions

β-NaGdF4:Yb3+/Er3+ nanoparticles (NPs) co-doped with Mo3+ ions were prepared for the first time using a solvothermal process at 300 °C. The influence of the doping concentration of Mo3+ ions on the growth and upconversion (UC) luminescence properties of the resulting β-NaGdF4:Yb3+/Er3+ nanocrystals were investigated in detail. The morphology and size of the β-NaGdF4:Yb3+/Er3+ nanocrystals were influenced by the concentration of the Mo3+ dopant ions. A possible mechanism for this behavior is proposed in this report. It was found that the upconversion luminescence intensity of the green emissions of the upconversion NPs co-doped with 10% Mo3+ ions was enhanced 9 fold and that the red emission was enhanced 4 fold. The experimental results suggest that the enhanced UC luminescence from the Mo3+ doped β-NaGdF4:Yb3+/Er3+ nanocrystals may have potential practical applications.