Polydopamine-regulated Growth And Patterning Of Metal Oxide/Sulfide Nanostructures In Wet Chemical Bath

Metal oxide and sulfide nanomaterials grown on different substrates were widely used in many fields,such as microelectronics,optoelectronic devices,sensor,energy storage and conversion.Regulation of their grown in a spatially defined manner to achieve patterning plays an important role for both fundamental research and practical applications.Polydopamine(PDA)is a mussel-inspired biopolymeric film and it can be formed on eventually any tpyes of substrates.The method of regulating the growth and patterning of metal oxide/sulfide by PDA film is suitable to the surface of various materials.Moreover,PDA can coordinate to metal ions effectivelydue to the presence of abundant phenolic hydroxyl and other functional groups on its surface.Therefore,it is expected to initiate/inhibit growth of metal oxide/sulfide nanomaterials with PDA film for patterning of these nanomaterials,if considering the fact that there have been a variety of available methods for patterning of PDA film,such as lithography,transfer printing,photo initiation polymerization,etc..In this paper,the influence of PDA film on the wet chemical growth of zinc oxide(Zn O)nanorods,tungsten oxide(WO3)precursor nanosheets and cadmium sulfide(CdS)film was studied in details.It was found that PDA demonstrates sharply different effect on the growth of three nanomaterials,and the possible underlying mechanism was discussed.Patterned growth of three nanomaterials was achieved on different substrates by patterning PDA with droplet polymerization method,transfer printing and UV light oxidation,respectively.The work consists of the following three parts:1.The effects of PDA film on the chemical bath deposition of ZnO nanorods on glass substrate were investigated.The results showed that PDA film can inhibit the growth of ZnO nanorods,even on Fe3+-activated substrate or ZnO-seeded surface.The underlying mechanism was further studies by Raman spectrum,Fourier transform infrared spectroscopy(FTIR)and X-ray photoelectron spectrum(XPS)and found to be tightly associated with the unique coordination property of PDA surface.2.Based on the finding in Part 1,patterned ZnO nanorods were grown on different substrates by pre-patterning PDA film by droplet polymerization method,transfer printing and UV light oxidation.Results suggest that it is possible to achieve patterned chemical bath deposition of ZnO nanorods by pre-pattering of PDA films.The patterning shows good spatial resolution and is applicable to wafer-size substrates.3.Patterned WO3 precursor nanosheets and CdS films on the surface of PET were prepared by using PDA as a spatially defined regulation layer in wet chemical bath and the possible mechanism was discussed.Results suggest that theinteraction between PDA film and the metal precursor is critical on the growth of nanostructuresdifferent interaction modes lead to totally different regulation effect,such as promotion or suppression.The findings disclosed in this thesis may offer useful guidance for the achievement of patterned growth of metal oxide and sulfide nanomaterials in a broad variety of fields.