Cationic Surfactant Assisted Sonochemical Synthesis of Nd3+ Doped Zn2SiO4 Nanostructures for Solid State Lighting Applications

Abstract

.For the first time cationic surfactant assisted ultrasound synthesis route has been used for the preparation of pure and Nd3+ (0.5-9 mol %) doped Zn2SiO4 nanophosphors. The shape, size and morphology of the products were tuned by controlling the various experimental parameters. The final product was well characterized by sophisticated techniques viz. powder X-ray diffraction (PXRD), Ultraviolet visible spectroscopy (UV-Vis) and photoluminescence (PL). The powder X-ray diffraction patterns confirmed that the synthesized samples exhibit hexagonal phase without any impurity. The DRS spectra showed major peaks at 275, 360, 529, 586, 680, 742 and 806 nm due to the transitions of the 4f electrons of Nd3+ from the ground-state 4 I9/2 to 2 F5/2, 4 D3/2 + 4 D5/2 + 2 I11/2, 2 K13/2 + 4 G7/2 + 4 G9/2, 4 G5/2 + 2 G7/2, 4 F7/2 + 4 S3/2, 4 F5/2 + 2 H9/2 and 4 F3/2 respectively. The band energy gap (Eg) of the samples were estimated and found to be in the range 5.32 – 5.52 eV. Under 421 nm excitation, PL spectra exhibit strong near ultraviolet emission peaks at ~ 444 nm, 459 nm and 520 nm were attributed to 2 P3/2→ 4 I13/2, 2 P3/2→4 I15/2, 1 I6→3 H4, 2 P1/2→4 I9/2 and 4 G7/2→4 I9/2 transitions respectively. The photometric studies indicate that the synthesized Zn2SiO4: Nd3+ nanophosphors can be tuned from blue to pale green by varying the dopant concentration. The current synthesis route is rapid, environmentally benign, cost-effective and useful for industrial applications such as solid state lighting and display devices.