Contents lists available at ScienceDirect Ceramics International journal homepage: www.elsevier.com/locate/ceramint Mn doped zinc silicate nanophosphor with bifunctionality of green-yellow emission and magnetic properties K. Omri a, ⁎ , O.M. Lemine b , L. El Mir a,b a Laboratoire de Physique des Matériaux et des Nanomatériaux Appliquée à l′Environnement, Faculté des Sciences de Gabès, Cité Erriadh Manara Zrig, 6072 Gabès, Tunisia b Al-Imam Mohammad Ibn Saud Islamic University (IMISU), College of Sciences, Department of Physics, Riyadh 11623, Saudi Arabia ARTICLE INFO Keywords: Zn 2 SiO 4 Nanophosphor Sol-gel Luminescent properties Magnetic properties ABSTRACT Luminescent-magnetic bifunctional Mn 2+ -doped Zn 2 SiO 4 (ZSMn 2+ ) nanophosphor were synthesized by the sol- gel technique and characterized by X-ray diffraction (XRD), UV–vis absorption, transmission electron microscopy (TEM), photoluminescence (PL) and SQUID. The Mn 2+ -doped effects of zinc silicate (ZS) upon the emission intensity and decay time were investigated under 4.86 eV excitation. Mn 2+ -doped ZS nanopho- sphor exhibits predominant visible emission under 4.86 eV ultraviolet light excitation, and the trend of their color changes from green to yellow are simultaneously realized in single-phase. The ZS nanophosphors exhibit green and yellow luminescence, depending on their crystal structure, which can vary with the preparation conditions. The green peak at at 2.37 eV is due to α– phase, while the yellow peak centered at 2.15 eV is due to the β– phase. The two phases are diamagnetic at room temperature but become ferromagnetic at 5 K. It was found that α-ZSMn 2+ phase has a higher saturation than the β-ZSMn 2+ phase. The correlation between the optical, structural and magnetic properties of nanophosphor is discussed in detail. 1. Introduction In recent years, the phosphor has attracted increasing attention because of its applications to solid-state lighting, display devices, detector systems and luminous paint with long persistent phosphores- cence [1]. A phosphor is generally composed of a transparent micro- crystalline host and a luminescence activator formed by impurity metallic atoms intentionally incorporated [2,3]. A large number of transition metal ions have been used as the luminescence activators of phosphors, especially divalent transition metal ions that generally exhibit stable emission due to the d–d electron transition [1,3]. Usually, ZSMn 2+ materials have been recognized as an efficient green nanophosphor extensively used in electroluminescent devices, PDPs, cathode ray tubes (CRTs) [2–4], and fluorescent lamps on account of its strong luminescence, high color purity, and long lifetime [2]. In the process of display application, the emission intensity and the decay time of a phosphor are of great significance. The commercially available green phosphor ZSMn 2+ has several advantages above-mentioned, which can give off green broad band emission, but long decay time for PDPs. It is well known that the silicate based phosphor materials are being used in luminescence display applications for a long time due to their excellent luminescence properties and their easy availability in nature [3]. Rare earth ions and/or transition metal ions are used as phosphor activators [3–5]. ZS is an excellent host material due to its high refractive index (∼1.7) and large band gap (∼5.5 eV) [6,7]. Mn 2+ doped ZS (green) is extensively used in fluorescent lamps, cathode ray tubes (CRT) and optoelectronic display panels [8]. The luminescence in blue, green and red colors may be obtained by doping with Eu 3+ , Ce 3+ , and Mn 2+ ions, respectively [9,10].. Therefore, the sol–gel process refers broadly to the room temperature solution routes for preparing oxide materials. High temperature is necessary of SZMn to improve the crystallinity and thus greatly limit their application [6]. SZMn with triclinic structure having 5.5 eV optical bandgap, which indicates in SZ is transparent for light possessing wavelength greater than 250 nm [11]. Over the last decade, many methods for the synthesis of SZMn have been reported including hydrothermal [6], co-precipitation [9], sol–gel technique [12]. Diverse studies reveal dielectric, optical and catalytic properties of SZ composite [10,12]. El Ghoul et al. [12] grew β-Zn 2 SiO 4 :V, composite inside oxidized porous silicon by annealing zinc and manganese salts up to 1500 °C for 120 min as a major product, but α-Zn 2 SiO 4 :V becomes dominated phase by decreasing the annealing temperature to more than 1200 °C. Rivera-Enríquez et al. [13], studied the microstructural and optical properties of α- and β- ZSMn nanoparticles obtained by a co-precipitation method. Transition http://dx.doi.org/10.1016/j.ceramint.2017.02.091 Received 23 January 2017; Received in revised form 20 February 2017; Accepted 20 February 2017 ⁎ Corresponding author. E-mail address: omrikarim16@yahoo.fr (K. Omri). Ceramics International 43 (2017) 6585–6591 Available online 21 February 2017 0272-8842/ © 2017 Elsevier Ltd and Techna Group S.r.l. All rights reserved. MARK