Enhanced temperature sensing response of upconversion luminescence in ZnO-CaTiO3: Er3+/Yb3+ nano-composite phosphor

Upconversion emission and temperature sensing of the Er3+/Yb3+ doped ZnO-CaTiO3 nano-composite phosphor is studied by varying the ZnO concentration. The XRD and EDX studies reveal the formation of composite phase when ZnO doping exceeds above 10 mw%. Five prominent upconversion emission bands at 410, 492, 524, 545 and 662 nm corresponding to H-2(9/2) -> I-4(15/2), F-4(3/2) -> I-4(15/2), H-2(11/2) -> S-4(3/2) -> I-4(15/2) and F-4(9/2) -> I-4(15/2) transitions, respectively are found under 980 nm excitation from a diode laser. On the basis of rise time analysis it was found that energy transfer process is responsible for the intense upconversion emission. Large reduction in decay time of S-4(3/2) level is observed on the ZnO incorporation in host matrix. Moreover, the absolute sensor sensitivity, relative sensor sensitivity and calculated color coordinates of the samples are also determined. These results indicate the potentiality of this composite phosphor for various applications. (C) 2015 Elsevier B.V. All rights reserved.