Upconverting Y2SiO5:Yb3+-Eu3+ phosphor for luminescent and surface assisted Raman enhancement

Yb3+-Eu3+ co-doped Y2SiO5 phosphor was synthesized by the co-precipitation method. The structural and optical properties of the synthesized phosphor were investigated using XRD, FTIR, Raman spectroscopy, FESEM, Fluorescence microscopy, and upconversion emission studies. Photoluminescence upconverting spectra under 980 nm NIR laser diode excitation exhibited characteristic emission bands of Eu3+ ions corresponding to the 5D0→7Fj (j = 0-2) transitions. The upconverting mechanism has been explained through the energy level diagram, where, possible co-operative energy transfer takes place from Yb3+ + Yb3+ → Eu3+. The overall emission colour has been noted in the reddish-white colour region using the CIE 1931 chromaticity coordinates diagram. The synthesized phosphor is used for making a non-plasmonic SERS substrate to study the surface-assisted Raman mode enhancement by probing the RhB dye molecule. The calculated enhancement factor (EF) is ~5.52 × 102. A charge transfer-mediated mechanism has been explained by fluorescence microscopy. Experimental results indicate that Y2SiO5:Yb3+-Eu3+ phosphor is a promising material for next generation luminescent and non-plasmonic surface-assisted Raman enhancer applications.