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Near infrared – emitting Zn2SiO4 powders produced by high energy planetary ball milling technique

The near infrared-emitting Zn2SiO4 powders were produced by high-energy planetary ball milling of ZnO and SiO2 powders followed by annealing in air environment and at different temperatures. The surface morphology, crystal structure, chemical composition and optical properties of the obtained samples were investigated by means of field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), Raman spectroscopy and photoluminescence measurements (PL) at room temperature. | Vietnam Journal of Science and Technology 56 (1A) (2018) 212-218 NEAR INFRARED – EMITTING Zn2SiO4 POWDERS PRODUCED BY HIGH-ENERGY PLANETARY BALL MILLING TECHNIQUE L. T. T. Vien1, *, Nguyen Tu1, 2, *, N. Tri Tuan3, N. D. Hung1, D. X. Viet1, N. T. Khoi1, P. T. Huy1 1 Advanced Institute of Science and Technology (AIST), Hanoi University of Science and Technology (HUST), N0 01 Dai Co Viet, Ha Noi, Viet Nam 2 Physics Department, Quy Nhon University, Quy Nhon, Viet Nam 3 College of Science, Can Tho University, 3/2, Ninh Kieu, Can Tho, Viet Nam * Email: lethithaovien@qnu.edu.vn and tunguyenqn@gmail.com Received: 15 August 2017; Accepted for publication: 31 March 2018 ABSTRACT The near infrared-emitting Zn2SiO4 powders were produced by high-energy planetary ball milling of ZnO and SiO2 powders followed by annealing in air environment and at different temperatures. The surface morphology, crystal structure, chemical composition and optical properties of the obtained samples were investigated by means of field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), Raman spectroscopy and photoluminescence measurements (PL) at room temperature. The analysis indicates the formation of Zn2SiO4 phase with annealing temperature of 1250 C. The size of Zn2SiO4 nanoparticles depends strongly on annealing temperature. Photoluminescence investigation reveals that the optimal annealing temperature for almost only near-infrared emission ( 740 nm) is 1250 oC. The origin of this peak can be attributed to the energy transfer from non-bridging oxygen hole centers (NBOHs) to zinc interstitial (Zn i) and oxygen vacancy (V o ) states in the Zn 2 SiO4 host lattice. These results demonstrate that we might be able to produce the Zn2SiO4 powders for applications in high CRI white light emitting diodes by a simple and low-cost method. Keywords: Zn2SiO4 powders, photoluminescence of Zn2SiO4, near infrared. 1. INTRODUCTION Zinc silicate (Zn2SiO4) is a well known mineral that .