Red fluorescence in LaF_3: Nd~(3+), Sm~(3+) nanocrystals grown by rapid microwave assisted synthesis: A comparative analysis of vibrational, thermal and electrical properties

摘要

Nanodiscs and nanorods of LaF_3: Nd~(3+) , Sm~(3+) (LFNS) have been obtained by new rapid microwave assisted synthesis using deionized water and methanol as solvents. Structural analysis shows a hexagonal crystal structure with particle size lying between 6 and 20 nm. FTIR, FT-Raman and thermal studies show the presence and removal of surface groups which make LFNS water soluble. Annealed samples indicate adsorption of atmospheric CO_2. Narrow size distribution of particles and presence of wide transparency window desirable in optoelectronic applications have been detected in UV-visible spectra. The SHG efficiency is seen to be enhanced in methanol. Photoluminescence studies show emission of red (654 nm) fluorescence. Dielectric studies indicate a dc conduction mechanism with involvement of the real part of dielectric constant in the process of polarization.