The Preparation Of Si-based Micro-Nanostructure Materials And Large Exposed(001) Surface Titanium Dioxides

In combination with the advantages of silicon-based solar cells and organic solar cells,Silicon-based Organic/inorganic Hybrid Solar Cells（denoted as SOHCs）have been widely investigated by global researchers.In this hybrid structures,the modification and optimization of silicon crystalline surface can effectively reduce the light reflection and improves the photoelectric conversion performance of PV devices.Recently,due to the excellent photocatalytic activity produced by its high surface energy,the anatase TiO₂nanomaterial with large exposed（001）surface photocatalyst has become a research hotspot,which may have potential applications in photocatalysis,solar cells and other fields.In this dissertation,we proposly prepared silicon-based micro/nano structures for SOHCs devices,meanwhile,we also synthesized and explored the adsorption properties of{001}faceted anatase TiO₂ photoanodes,which supplies some important information for future research of SOHCs devices.1.Pyramid-like silicon were prepared by water bath method in alkali solution,which laid the foundation for SOHCs research.The pyramid-like silicon material with great balanced distribution and lowest reflectivity was prepared in etching solution with C_KOH=0.10 mol/L,C_IPA=0.10 mol/L at 80℃for 20 min.2.The unique pyramid-like/nanowire composite was formed via metal-assisted chemical etching method.The length of nanowires on pyramid surface increased with the etching time,which reduced the reflectivity,but the pyramid structure might be destroyed when the etching time up to 4.5 mins combined with the increasing reflectivity.Meanwhile,the H₂O₂ concentration changes the growth direction of nanowires on the pyramid surface.Owing to its high light trapping ability,the current density of the silicon pyramid/nanowire composite is the highest.3.The anatase TiO₂ with large exposed（001）surface was studied because the theoretical results predicted that this surface has high reactivity.The XRD and SEM results indicate that 4 hours’reaction time produce the highest ratio of exposed（001）surface.A dense TiO₂ film was prepared by sol-gel method was introduced as the substrate,due to its could effectively overcomes the contact between electrolytes to FTO surface,which helps the A001 photoanode achieving its saturation photocurrent.4.The adsorption and degradation processes of aromatics with different functional groups on anatase TiO₂（001）surface was preliminarily explored.The similar slow reaction constant shows that the benzene ring is mainly degraded by the hydroxyl radicals which are produced by the water.The different fast reaction constants prove that the interfacial reaction ability is related to the strength of organic functional groups adsorbed on（001）surface.the highest kinetics constants of fast process for KHP and benzoic acid indicate that the carboxyl compound is more favourably adsorbed on the anatase（001）surfaces than hydroxy and aldehyde compounds.It can be suspected that the carboxylic compound organic molecules could possibly increase the efficiency of electron transportation when the anatase TiO₂ with large exposed（001）surface was used as a buffer layer in SOHCs.