ZnS quantum dot based nanocomposite scintillators for thermal neutron detection

Water-soluble ZnS quantum dots (QDs) were synthesized using a co-precipitation method. Both undoped and Eu3+-doped ZnS QDs showed emission bands peaking at around 420 nm. The highest photoluminescence (PL) quantum yield (QY) was measured to be 17% for undoped ZnS QDs capped with SiO2. Thermal neutron induced pulse height and pulse shape spectra were measured for composites composed of (LiF)-Li-6 nanoparticles, undoped ZnS QDs, and poly(vinyl alcohol) (PVA) matrix. The pulse height spectra from the nanocomposites were analyzed with a track-structure model. The pulse decay time of scintillation photons is 10-30 ns. The fast decay rates and clear pulse height peaks induced by thermal neutrons indicate that ZnS QD based nanocomposites are promising scintillators for detecting high-flux thermal neutrons. 2010 Elsevier B.V. All rights reserved.