Strong near-infrared upconversion luminescence of the Er3+/Y3+ co-doped YbVO4 phosphor for multimode optical temperature measurement.

ABSTRACT

This study explored the enhancement of near-infrared emissions in YbVO4 Er3+ through Y3+ ion doping under a 980 nm laser excitation. The phosphor exhibits weak green emissions at 527 nm (2H11/2 â†’ 4I15/2) and 553 nm (4S3/2 â†’ 4I15/2), red emissions at 654 nm (4F9/2 â†’ 4I15/2), and a strong near-infrared emission at 803 nm (4I9/2 â†’ 4I15/2). Optimal doping concentration of Y3+ ion in YbVO4 0.02 Er3+ was determined to be 0.1, resulting in a 7.6-fold enhancement of near-infrared luminescence. This enhancement is attributed to defect bands facilitating energy transfer from green and red levels to the near-infrared levels. Furthermore, a multi-mode temperature sensor based on YbVO4 Er3+/Y3+ was developed, offering four distinct temperature sensing modes TCEL of 2H11/2/4S3/2, NTCEL of 2H11/2/4F9/2 and 4S3/2/4F9/2, and single luminescence emission intensity of 4I9/2 energy level. The sensor demonstrates maximum relative sensitivities of 1.17 % K-1 at 298 K, 0.66 % K-1 at 298 K, 0.41 % K-1 at 298 K and 1.29 % K-1 at 673 K. YbVO4 Er3+/Y3+ phosphor exhibits high temperature sensitivity, showcasing significant potential for optical temperature sensing applications.