Activation of zirconia nanophosphors with Eu3+to demonstrate multifunctional optical applications

Pristine ZrO2 and Eu3+ activated ZrO2 nanophosphors were synthesized by urea assisted solution combustion method. The synthesized nanophosphors were characterized by Powder X-ray diffraction (PXRD), Field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and photoluminescent (PL) spectroscopy for their structural, morphological, surface, vibrational and luminescent studies. The crystal structure and phase transformation were studied by PXRD which was supported well by XPS and FTIR results. FESEM studies reveal the porous morphology due to the combustion synthesis. XPS results reveal that activator Eu was predominantly present in the +3 oxidation state in the nanpohosphor. PL emission spectra of Eu3+ activated zirconia show characteristic reddish emission corresponding to 5D0 -> 7FJ (J = 0, 1, 2, 3, and 4) transitions of Eu3+ ion. Photometric parameters were calculated to check the possible application of the nanophosphors for solid-state lighting. The high color purity -94% of the synthesized phosphors indicates their application in phosphor-converted white light-emitting diodes (pc-wLEDs). The fluorescence intensity ratio (FIR) of non-thermally coupled levels 5D0 -> 7F2 and 5D0 -> 7F3 were used to calculate the temperature. At 623 K, a maximum relative and absolute sensitivity of 0.11% K-1, and 0.76% K-1 was observed. The possible anti-counterfeiting application of ZrO2:Eu3+ has been tested using a standard screenprinting procedure. The high contrast fingerprints of the synthesized phosphor taken under near-ultraviolet (nUV) light indicate that the synthesized phosphor can be used for latent fingerprinting applications. All these results indicate that Eu3+ activated zirconia has the potential to be used as multifunctional material.