Quantum Dot Loaded Nanocomposite Plastic Scintillators

Abstract

Exciton confinement within nanoparticle quantum dots results in electronic and optical properties not exhibited within bulk material semiconductors of the same composition. This thesis reports how loading CuInS/ZnS quantum dots in polyvinyl toluene (PVT)-based plastic scintillator increased peak emission intensity and wavelength. Five core/shell quantum dot materials were dispersed within toluene and characterised for suitability in loaded scintillators: CdSe/ZnS, ZnCdSe/ZnS, ZnCdSeS, ZnCuInS/ZnS, and CuInS/ZnS. The CuInS/ZnS quantum dots exhibited the brightest emission and a 180±1 nm Stokes shift large enough for negligible selfabsorption. Various masses of CuInS/ZnS quantum dots were loaded into EJ-290 plastic scintillator casting resin with three different loading regimes: homogeneous, sedimented layer, and a hybrid between the two. Loading within these casting scintillators was confirmed and characterised through energy-dispersive X-ray spectroscopy. Transmission spectra of the quantum dot loaded and unloaded cast scintillators were obtained and showed the presence of CuInS/ZnS increased the opacity, particularly for the highly concentrated layers in the sedimented and hybrid