Gamma irradiation effect on photoluminescence from functionalized LaF3:Ce nanoparticles

• Oleic acid coated and uncoated LaF3:Ce of 10 and 18 nm size were synthesized.
• Gamma irradiation caused breach in the oleic acid cover.
• A decrease in absorption and PL intensity with increase in gamma dose was observed.
• PL spectral structure did not change even at 6.19 kGy dose.
• Nano LaF3:Ce, seems to be more hard on the radiation unlike other alkaline halides.

Oleic acid coated and uncoated LaF3:Ce nano-phosphor particles were synthesized by a co-precipitation method. Nanoparticles were characterized for their structure, organic coating and optical behavior using an X-ray diffraction, a Transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FTIR), UV–vis absorption and Photoluminescence spectroscopy. Sizes of nanoparticles were measured from TEM images and were also estimated using the Scherer formula. UV–vis absorption, Photoluminescent and FTIR measurements were done with nanoparticles before and after gamma irradiation up to a dose of 6.19 kGy. The uncoated nanoparticles exhibit emission only at 305 nm when exited with 250 nm. The oleic acid coated nanoparticles exhibit emissions at 308 and 361 nm when exited with 252 nm. Dependence of photo luminescent intensity on gamma dose was studied and the changes were attributed to radiation induced defect traps and also to the breach or damage in the capping material.