Euphorbia tirucalli mediated green synthesis of rose like morphology of Gd2O3:Eu3+ red phosphor: Structural, photoluminescence and photocatalytic studies

Abstract

Eco-friendly, cost effective and bio template route was used for the preparation of cubic Gd2O3:Eu3+ nanophosphors using Euphorbia tirucalli (E. tirucalli) plant latex as fuel. As – formed Gd2O3:Eu3+ (7mol%, 1–7ml), calcined Gd2O3:Eu3+ (7mol%, 1–7ml) and Gd2O3:Eu3+ (1–11mol%, 7ml) samples were characterized using XRD, SEM and UV–Vis absorption spectrophotometer. With increase in latex concentration, the nanophosphor gets transformed from nano plates to rose – like nanoflowers with size varying from 20 to 30nm. X-ray diffraction pattern of as – formed product shows hexagonal Gd (OH)3: Eu3+ phase and it converts to pure cubic phase of Gd2O3:Eu3+ on calcination at 600°C for 3h. Rietveld refinement of Gd2O3:Eu3+ (7mol%, 7ml) revealed the presence of cations in the 8b (0.25, 0.25, 0. 25) and 24d positions (−0.0287, 0.00, 0. 25) and the anions in the 48e positions (0.39, 0.15, 0. 37) with space group Ia-3(206). The photoluminescence intensities of transitions between different J levels depend on the symmetry of the local environment of Eu3+ ion activators and the high ratio of intensity of (5D0→7F2) and (5D0→7F1) provides the conclusion that Eu3+ ion occupies sites with a low symmetry and without an inversion centre. The chromaticity and the CIE coordinates were very close to the standard red color region. The absorption observed in the excitation spectra shows the suitability of the nanophosphor obtained in this study for getting excited in UV, NUV and visible regions for variety of display applications. Further, the Gd2O3:Eu3+ (7mol%, 1–7ml) samples were experimented towards the photocatalytic behavior on Congo red (CR) and correlated with emission of PL intensity. The decolorization of dye was found to decreased from 83 to 54% with increase in the plant latex concentration.