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Novel eco-friendly synthesis of neodymium doped zinc silicate phosphor based waste glass ceramic: structural, thermal and luminescence properties ABSTRACT A novel Nd 3+ doped Zn 2 SiO 4 (at Nd 2 wt%) phosphor have been synthesized at different sintering temperature (600-1000 °C) by low cost solid state route. For the first time, the ecofriendly based glass ceramic phosphor were produced by utilizing waste soda lime silica glass (SLS) and ZnO as precursor. The obtained samples were investigated in terms of thermal properties by DSC technique and the results showed a possible crystallization peak around 620 °C. The crystalline phase formation by XRD revealed α-willemite at lower temperature of 800 °C. The analysis by FTIR exhibit the existence of ZnO 4 and SiO 4 structural bonding. The microstructure analysis by FESEM revealed the evolvement from irregular blocks to crystalline structure. EDX analysis confirmed the presence of main element contained in the samples. UV-Vis spectroscopy shows absorption peaks from the ground 4 I 9/2 state to various excited energy level of Nd 3+ ion in 4f 3 configuration. Under diode laser excitation of 800 nm photoluminescence, the samples shows possible upconversion emissions in the blue, green, orange and red region. Possible mechanism of upconversion were also studied proposing the suitability of Nd 3+ :Zn 2 SiO 4 based waste glass ceramic for solid state laser.

Currently, many researchers interested studying waste materials to recycle them or reuse them in new products. From the sustainable perspective development, it is necessary to implement new technologies to help reduce waste and thus minimize the environmental problems associated with disposal. In this study, the preparation of SiO2-Na2O-CaO-P2O5 (SNCP) glass-ceramic is composed of Soda Lime Silicate (SLS), Clam Shell (CS), Na2CO3 and P2O5 in the ratio of 50: 25: 20: 5 respectively. The waste materials that were used for fabricate glass-ceramic are SLS and CS. All the compounds were mixed to fabricate the SNCP glass-ceramic through solid state reaction. The samples were investigated through X-ray diffraction (XRD), field emission microscope (FESEM) and density measurement. The samples were sintered at temperature 550°C, 650°C, 750°C, 850°C until 950°C. The main phase obtained from XRD analysis is Sodium Calcium Silicate, Na2CaSiO4 with cubic crystal system at 550°C. The highest intensity phase of the diffraction peak is (220) and at the angle 33.7°. There was new peak presence at right side of the main phase Na2CaSiO4, which belong to Silicon Phosphate, SiP2O7 at 650°C and 750°C.When heat treatment increased at 850°C - 950°C, the main phase is Combeite, Na4Ca4(Si6O18) at diffraction peak (220) with rhombohedral crystal system which is assigned to high crystallization temperature (Tc). The density of samples increases at 550°C - 750°C and decreases when heat treatment 850°C - 950°C. Sample density decreases at heat treatment 850°C - 950°C due to increases of sample lattice parameter. FESEM analysis showed that the grain size and porosity increased when the heat treatment increased.

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