Luminescent lanthanides doped NaGdF4 nanoparticles–plastic nanocomposites for gamma ray scintillation

Abstract

Plastic gamma ray scintillators exhibit significant application potential in the fields of portal monitoring, medical imaging, and industrial screening. High loading of high-atomic number components enhances gamma photoelectric attenuation but often leads to a drastic decrease in light yield, which significantly restricts the detection sensitivity. In this work, core-shell structured luminescent NaGdF₄ nanoparticles doped with Tb (15 mol%) and Ce (10 mol%) as activators with particle sizes around 6–7 nm were developed. Plastic nanocomposites were fabricated by loading the nanoparticles together with 2-(4-tertbutylphenyl)-5-(4-biphenylyl)-1,3,4-oxadiazole, 4-Bis(5-phenyl-2-oxazolyl)benzene, and 9,9-dimethyl-9H-fluorene in polyvinyltoluene matrix. The nanocomposites loaded with 20 % and 40 % of NaGdF₄:15 Tb@NaGdF₄ demonstrate gamma light yields of 8490 Photons/MeV and 7020 Photons/MeV, which are 8.5 % and 14.3 % higher than those of NaGdF₄-loaded counterparts. Meanwhile, gamma pulse spectroscopies of 20 wt% and 40 wt% nanoparticles-loaded nanocomposites show photopeaks with energy resolutions of 10–12 %, and the nanocomposites loaded with 40 % nanoparticles also maintain a fast decay time of ∼2 ns.