Improved photoluminescence and thermal stabilization of glycine functionalized LaF3: Ce nanoparticles useful in bioimaging and biotagging

Abstract

LaF3:Ce nanocrystals doped with glycine have been synthesized from water soluble chlorides and subsequent irradiation by microwave. The XRD spectra confirms the hexagonal phase structure with cell parameter a = b = 7.173 Å and c = 7.211 Å with space group P3cl and particle size of 15 nm. The value is in confirmation with the density functional calculation of structural properties by LDA and GGA potentials predicting merohedral twinned structure of tysonite like compounds. The SEM and TEM images show narrow distribution of nanoparticles with hexagonal and assorted morphology having particle size of 25 nm. The SAED pattern confirms the formation of crystallinity of nanocrystals and traces of different elements in the nanocrystals have been detected by EDAX pattern. The FTIR spectrum shows peaks due to weak organic attachments indicating the capping on the core LaF3:Ce by the functional groups of the organic ligands. The UV spectrum shows the presence of multiple absorption edges corresponding to band gap energies at 5.17 eV, 4.87 eV,4.28 eV,3.40 eV indicating the quantum dot structure of inorganic nanocrystals. The photoluminescence of the nanocrystals has been observed by excitation and emission spectra. The peak at 616 nm shows emission of red fluorescence, indicating its possible applications in bio imaging and biotagging. The TGA/DTA graph shows the stable phases of the nanocrystals synthesized.