Microwave synthesis and studies room temperature optical properties of LaF$_3$: Ce$^{3+}$, Pr$^{3+}$, Nd$^{3+}$ nanocrystals

Lanthanum fluoride (LaF$_{3}$: Ce$^{3+}$, Pr$^{3+}$, Nd$^{3+}$) was synthesized by water soluble LaCl$_{3}$ + CeCl$_{3}$+ PrCl$_{3}$ + NdCl$_{3}$ and NH$_{4}$F as starting materials in de-ionized water as solvent using microwave assisted technique. The structure of LaF$_{3}$: Ce$^{3+}$, Pr$^{3+}$, Nd$^{3+}$ nanocrystals analyzed by XRD and TEM analysis is found to be in hexagonal structure and average crystalline particle size is $20$ nm (JCPDS standard card (32-0483) of pure hexagonal LaF$_3$ crystals). The absorption edge in UV spectra is found at $250$ nm corresponding to energy of $4.9$ eV. It further shows a wide transparent window lying between $200$ nm–$800$ nm. For LaF$_{3}$: Ce$^{3+}$, Pr$^{3+}$, Nd$^{3+}$ nanocrystals emission of blue color ($458$ nm) has been observed with at an excitation wavelength of $254$ nm. The measured relative second harmonic generation (SHG) efficiency of LaF$_{3}$: Ce$^{3+}$, Pr$^{3+}$, Nd$^{3+}$ in de-ionized water with respect to KDP crystal is $0.186$.