서강대학교

초록/요약

Cuprous oxide (Cu2O) is a promising semiconducting material for photocatalysts and spintronics device because of its properties with narrow band gap (2.17 eV) and outstanding mobility of minority carriers (140 meV). In this study, cubic and octahedral shaped Cu2O nanoparticles are fabricated with and without use of surfactant, poly(N-vinyl-2-pyrrolidone) (PVP). Both cubic and octahedral shaped Cu2O particles are revealed to single crystals characterized with XRD, TEM and HRTEM measurement. Photocatalytic activities of cubic and octahedral shaped Cu2O particles present different photocatalytic properties which is determined by photodegradation process of methyl orange (C14H14N3NaO3S, MO). Ferromagnetism of cuprous oxide (Cu2O) is induced through its interaction with chemisorbed PVP that causes 3d orbital alteration. The origin of magnetism is 3d orbital alteration of Cu (I) ions, which ideally have fully occupied 3d orbitals of d10 electronic configuration. The alteration is caused by forming coordination between O atoms of PVP and Cu (I) ions of the surface along the xy-orbital plane of Cu (I) ions. Furthermore, ligand-to-metal charge transfer has been occurred from O atoms of PVP to the Cu (I) ions. It increases the unpaired electron density of Cu (I) ions that leads to larger hyperfine coupling constant of EPR spectra. According to EPR spectrum appeared in septet hyperfine splitting, in addition, Cu2O capped with PVP might have Cu-Cu interaction on the surface through the O atoms of PVP.