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

A series of bifunctional NaYF 4 microcrystals doped with Yb 3+ /Er 3+ 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 ∼540 nm green light from Er 3+ -4 f n electronic transition 4 S 3/2 -4 I 15/2 , ∼657 nm red light from Er 3+ -4 f n electronic transition 4 F 9/2 -4 I 15/2 , and ∼407 nm violet light from Er 3+ -4 f n electronic transition 2 H 4 9/2 I 15/2 , under the excitation of 980 nm infrared light.It is found that the red emission is more sensitive to the doping of Yb 3+ ion than the green one, leading to the significant increase in the ratio of red emission to green emission with increasing concentration of Yb 3+ ion.In addition, the paramagnetic property was remarkably enhanced with increasing concentration of Yb 3+ ion which is ascribed to the substitution of nonmagnetic ion Y 3+ by the magnetic ion Yb 3+ with large magnetic moment.