Simultaneously tunable luminescence and magnetic properties in bifunctional NaYF4: Yb3+/Er3+ microcrystals

A series of bifunctional NaYF(4 )microcrystals doped with Yb3+/Er3+ have been successfully synthesized through a facile hydrothermal method. They have been characterized by XRD, SEM, photoluminescence spectra and the magnetization. These microcrystals can emit similar to 540 nm green light from Er3+-4f(n) electronic transition S-4(3/2): I-4(15/2), similar to 657 nm red light from Er3+-4f(n) electronic transition F-4(9/2)-I-4(15/2), and -407 nm violet light from Er3+-4f(n) electronic transition (H9/2I15/2)-H-4-I-4, I under the excitation of 980 nm infrared light. It is found that the red emission is more sensitive to the doping of Yb3+ ion than the green one, leading to the significant increase in the ratio of red emission to green emission with increasing concentration of Yb3+ ion. In addition, the paramagnetic property was remarkably enhanced with increasing concentration of Yb3+ ion which is ascribed to the substitution of nonmagnetic ion Yb3+ by the magnetic ion Yb3+ with large magnetic moment.