Synthesis and characterization of different shaped Sm₂O ₃ nanocrystals

Here, we demonstrate the synthesis of Sm₂O₃ nanoparticles, nanorods and nanoplates by solution-based techniques. The mechanism related to morphology control is proposed and discussed. The crystal phase of the Sm₂O₃ nanocrystal is tuned by varying the surfactant in the reaction. It is found that compressive strain is observed for lower temperature (600 °C) heated sample but reversal of strain appears at elevated temperature (900 °C). A chromatic change in photoluminescence (PL) emission with tuning the excitation wavelength has been observed. The PL emission is due to f-f electronic transition from excited states of ⁴G_5/2 of the Sm³⁺ ion. The PL emission bands at 610 and 656 nm are observed under excitation 370 nm, but bands centred at 545, 610 and 656nm are observed when the excitation wavelength is tuned to 400 nm. It is seen that the ratio between electric dipole and partially magnetic dipole contributions is maximum for nanorods followed by nanoplates and nanoparticles. Magnetic susceptibility study of the nanocrystals shows that the Sm³⁺ ion follows the well-known Van Vleck behaviour.