Simultaneously Control the Optical and Paramagnetic Properties of Bifunctional Na(Y 0.8-x Dy x Yb 0.18 Er 0.02 )F 4 Nanoparticles

Bifunctional Na(Y 0.8-x Dy x Yb 0.18 Er 0.02 )F 4 (x = 0,5%, 10%, 15%, 20%, 25%, 30%) nanoparticles (NPs) are synthesized by the solvothermal method. Green and red upconversion emissions and the paramagnetic property simultaneously highly depend on Dy 3+ content in Na(Y 0.8-x Dy x Yb 0.18 Er 0.02 )F 4 (x = 0, 5%, 10%, 15%, 20%, 25%, 30%). The tuning of upconversion emission intensity is resulted from the competition of the resonance energy transfer between Dy 3+ and Er 3+ , transition possibility of Yb 3+ → Er 3+ , and concentration quenching, which is depended on the doping level of Dy 3+ . It is found that the magnetization of Na(Y 0.8-x Dy x Yb 0.18 Er 0.02 )F 4 NPs nonmonotonously depends on the concentration of Dy 3+ ions, which indicates that there may be the occurrence of the magnetic coupling of Dy 3+ ions and antiferromagnetic coupling of Dy 3+ , Y 3+ , Yb 3+ , and Er 3+ ions. The optimal content of Dy 3+ ions for simultaneous control of photoluminescence emission and paramagnetic properties is 15%. These conclusions are important for tuning optical properties and magnetization in bifunctional NPs simultaneously.