Synthesis and spectroscopic analysis of NaCaYF6:Nd3+, Yb3+NIR emitting phosphor

Near Infra–red (NIR) emitting NaCaYF₆:Nd³⁺and co–doped with Yb³⁺phosphor has been prepared by hydrothermal synthesis. The formation of Gagarinite structure of the host matrix with space group P6₃/m was confirmed by XRD and Rietveld analysis. FESEM analysis confirms the spherical morphology along with the homogeneity, and mapping of elemental composition by EDS analysis. NIR emission at 1065 nm due to ⁴F_3/2→⁴I_11/2 electronic transition of Nd³⁺ ion upon the exposure to 577 nm light. The prominent PL emission at 994 nm from NaCaYF₆:Nd³⁺,Yb³⁺ phosphor was obtained due to ²F_5/2→²F_7/2 electronic transition of Yb³⁺ion. Yb³⁺ emission was sensitized by Nd³⁺ activator. The intensity of Yb³⁺emission increases at the cost of the Nd³⁺ luminescence. The results are ascribed to the energy transfer from Nd³⁺to Yb³⁺. The theoretical Judd-Ofelt (J-O) analysis was also reported to confirm the obtained luminescence behaviour and energy transfer (ET) mechanism of the phosphor. The obtained results specify that the phosphor has a potential application such as in–vivo, in−vitro imaging and NIR laser applications.