Structural and optical properties of green emitting Y 2 SiO 5 :Tb 3+ and Gd 2 SiO 5 :Tb 3+ nanoparticles for modern ligh
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Structural and optical properties of green emitting Y2SiO5:Tb3+ and Gd2SiO5:Tb3+ nanoparticles for modern lighting applications Sitender Singh, Devender Singh*
Received: 9 December 2019 / Revised: 14 February 2020 / Accepted: 30 August 2020 Ó GRINM Bohan (Beijing) Publishing Co., Ltd 2020
Abstract The optical and structural properties of Tb3? -doped yttrium and gadolinium oxyorthosilicate (Y2SiO5 and Gd2SiO5) phosphors were analyzed. The samples were synthesized via sol–gel combustion method using organic fuel. The phase purity and structural properties of the samples were determined via combined approach of powder X-ray diffraction, Fourier transformation infrared (FTIR) and transmission electron microscopy (TEM). X-ray measurements revel monoclinic crystal lattice with P21/c symmetry for both M2SiO5 (pure host) and M2SiO5:Tb3? (doped) silicates, irrespective of the nature of metal (Y or Gd), presence or absence of Tb3? in lattice and change in calcination temperature up to 1050 °C. FTIR analysis was applied to confirm the bonding of prepared materials. The appearance of bands corresponding to SiO4 tetrahedra (880–1020 cm-1) suggest the layered structure and support the diffraction measurements. TEM micrographs confirm the synthesis of spherical nanoparticles with filled morphology, narrow size distribution and slightly agglomerated crystallites of the samples. The elemental composition of prepared materials was determined using energy dispersive X-ray spectroscopy. The spectra show peaks only for elements assimilated within the host framework. The photoluminescence (PL) emission spectra of Tb3?-doped samples show 5D4 ? 7FJ (J = 3–6) transitions under 254 nm-excitation. The dominant peak at 544 nm for 5D4 ? 7F5 transition is responsible for the emission of green light on ultraviolet–visible excitation in both the Tb3?-doped host matrixes. Owing to advantageous properties like intense PL and high crystallinity, these S. Singh, D. Singh* Department of Chemistry, Maharshi Dayanand University, Rohtak 124001, India e-mail: [email protected]
nanophosphors could possess potential applications in the mercury free lighting sources and optoelectronic devices. Keywords Structural; Optical; Silicates; Luminescence; Optoelectronic
1 Introduction In recent years, the rare-earth ions doped phosphor materials have considerably been evaluated for their uses in the advanced display and lighting technology. The growth of this research field is due to extensive application of these materials in almost every device comprising the artificial production of light [1, 2]. The development of efficient phosphors requires suitable host matrix and activator ion. The requirement of activator ion is due to large band gap of host lattice. Rare earth ions are generally used as dopants due to presence of abundant energy levels. The phosphorconverted white light emitting diodes (pc-WLED) have been proved worthful in the field of lighting technology due to eco-friendly nature, extensive serving time, high brightn
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