Facile synthesis of p-type Cu2O/n-type ZnO nano-heterojunctions with novel photoluminescence properties, enhanced field emission and photocatalytic activities

Two kinds of Cu2O–ZnO nano-heteroarchitectures were fabricated through a hydrothermal method. By utilizing polyethyleneimine (PEI) as a binding agent, ZnO nanoparticles were uniformly self-assembled onto Cu2O micro structures. Photoluminescence (PL), field emission and photocatalytic activities of the composite samples were investigated and compared with those of the pure Cu2O samples. The results reveal that ZnO nanoparticles combined on Cu2O microstructures remarkably changed the PL signals, and significantly enhanced the field emission and photocatalytic activities. The novel PL properties, enhanced field emission and photocatalysis activities are attributed to the electron transition and the inhibition of photo-induced electron–hole pairs recombination, which stem from interfacial defect states and energy band differentials at the interface of Cu2O and ZnO. The surface nano-protrusions, large surface area and better dye adsorption induced by ZnO nanoparticles are responsible for the field emission and photocatalysis improvements as well.