Investigation of charge transport between nickel oxide nanoparticles and CdSe/ZnS alloyed nanocrystals

Abstract

Charge transport between nickel oxide nanoparticles and CdSe/ZnS alloyed core/shell nanocrystals is investigated. The crystal structure and composition of the nickel oxide nanoparticles are evaluated using X-ray diffraction, Raman and X-ray photoelectron spectroscopies. The nanoparticles are near-stoichiometric with very low defect densities. The optical properties of the materials are studied by measuring the absorbance and time resolved photoluminescence spectra. The band gap of the nickel oxide nanoparticles is around 4.42 eV. The CdSe/ZnS nanocrystals exhibit shorter average lifetimes when mixed with nickel oxide nanoparticle powder. The lifetime quenching can be attributed to the efficient charge transport from the CdSe/ZnS nanocrystals to nickel oxide nanoparticles due to the relative valence band alignment.