Thermally stable upconverting Na3Zr2(SiO4)2PO4: Er3+/Yb3+ phosphors for displays and optical thermometry

Abstract

The advanced new Er 3+ /Yb 3+ : Na 3 Zr 2 (SiO 4 ) 2 PO 4 (NASICON) monoclinic phosphors prepared by solid state reaction technique has been analyzed as upconverting materials. The crystal phase, structural parameters, surface morphology , different functional groups and bandgap of the synthesized phosphors have been analyzed. Under 980 nm continuous wave diode laser excitation, the codoping of Yb 3+ ions in the Er 3+ doped phosphors exhibit fascinating results. Stark sublevels observed in the upconversion emission have been used for the fluorescence intensity ratio (FIR) based thermometry. Relative & absolute sensitivity, thermal stability and temperature dependent CIE have been determined. The thermally stable Na 3 Zr 2 (SiO 4 ) 2 PO 4 : Er 3+ /Yb 3 phosphors with high color purity can be utilized in sensing, display and security purposes. Upon 980 nm excitation the UC emission obtained from Er 3+ /Yb 3+ doped Na 3 Zr 2 (SiO 4 ) 2 PO 4 phosphors have been utilized for temperature sensing and security ink application. • UC intensity enhancement of ~ 13 times has been observed with incorporation of Yb 3+ in Er 3+ doped Na 3 Zr 2 (SiO 4 ) 2 PO 4 upconverting phosphors. • Maximum absolute and relative sensitivity of the developed phosphor have been found to be 6.4 @ 393 K and 9.3 @ 303 K respectively with thermal resolution± 0.30 K at 303 K. • Thermal stability with activation energy ~ 0.30 eV has been studied upto 508 K.