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

• ZnO–CaTiO3: Er3+/Yb3+ nano-composite phosphor is prepared via co-precipitation technique.
• The presence of dual phase in XRD analysis shows the composite nature.
• Enhanced upconversion emission on 30 mw% ZnO doping in CaTiO3: Er3+/Yb3+.
• Enhancement in fluorescence based temperature sensitivity on ZnO doping.
• Excellent sensor sensitivity is observed in present sample.

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 2H9/2 → 4I15/2, 4F3/2 → 4I15/2, 2H11/2 → 4I15/2, 4S3/2 → 4I15/2 and 4F9/2 → 4I15/2 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 4S3/2 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.

Upconversion emission and temperature sensing of the Er3+/Yb3+ doped ZnO–CaTiO3 nano-composite phosphor is studied by varying the ZnO concentrations. The XRD and EDAX studies reveal the formation of composite phase when ZnO doping exceeds above 10 mw%. To 30 mw% of ZnO concentration the upconversion intensity was found to be optimum. Five prominent upconversion emission bands at 410, 492, 524, 545 and 662 nm corresponding to 2H9/2 → 4I15/2, 4F3/2 → 4I15/2, 2H11/2 → 4I15/2, 4S3/2 → 4I15/2 and 4F9/2 → 4I15/2 transitions, respectively are found under 980 nm excitation from a diode laser. The CIE color coordinate diagram is monitored and found that at different laser power the color coordinates are invariant and the purity in green color emission increases for optimum ZnO concentration. Consequently, the present nano-composite phosphor may be used as display devices and LEDs.Figure optionsDownload as PowerPoint slide