Enhanced Luminescence of L-Alanine Capped LaF₃:Ce Nanoparticles Useful in Biological Labeling

Hexahedral nanocrystals of L-Alanine [CH₃CH(NH₂)COOH] doped LaF₃:Ce (ALFC) of assorted sizes have been synthesized in deionized water using water soluble chlorides of lanthanides with subsequent microwave irradiation to reduce agglomeration. The average particle sizes obtained by XRD, SEM, and TEM have been 22nm, 37nm and 23nm respectively. The surface modification by functional groups of L-Alanine is observed in the FTIR and FT-RAMAN spectra and their decomposition is studied in TGA/DTA spectrum .The electron-phonon interaction of A_1gphonon mode and fundamental E_gphonon mode have been observed in far infra-red region by FT-RAMAN spectra. The UV-Vis spectrum shows multiple absorption edges corresponding to energies at E₁= 5.11eV, E₂= 4.47eV, and E₃=5.781eV which indicates the quantum dot nature of the nanocrystals and its application in optoelectronic devices. ALFC nanocrystals showed green color emission peak centered at 554 nm with their potential application in bio imaging and bio tagging.Keywords: nanostructures, fluorides, Transmission electron microscopy, Raman spectroscopy, Thermogravimetric analysis (TGA).