Photovoltaic And Electrochemical Properties For Nanostructured Multiple Oxides

Nanostructured multiple oxides have been considered as a kind of multifunctional composite materials with a widely potential application.Up to date,the synthesis of nanostructured multiple oxides is becoming a subject of intense interest.In this dissertation,we focus on the design and synthesis of nanostructured multiple oxides and their applications in energy conversation and energy storage devices.One of our aims is to improve the performance of dye-sensitized Zn2SnO4 solar cells via a surface treatment route,aothother is to design a unique hybrid nanostructure,ZnSn(OH)6 nanocubes coated by reduced GO,for highly reversible lithium ions storage.The main contents and results are as following:(1)A facile surface-treatment method by means of chemical-bath deposition is proposed for improving the photovoltaic performance of dye-sensitized Zn2SnO4 solar cells.After surface treatment,the best efficiency of 3.45%was achieved using dyes N719 and D131 as a co-sensitizer under AM 1.5(100 mW cm-2).Compared to the untreated Zn2SnO4 film,an enhancement of 13.5%was obtained.In fact,the adsorption amounts of N719 and D131 dyes were slightly decreased after the treatment.However,the decreased charge recombination rate and prolonged electron lifetime led to an obviously enhanced performance.Moreover,the slightly decreased conduction band edge of Zn2SnO4 provided an enhanced driving force for electron injection,which also had some effect on the increased Jsc and ?.(2)ZnSn(OH)6 nanocubes with a uniform size were synthesized by using a simple hydrothermal route and then combined with graphene sheets(rGO)via the electrostatic interaction.SEM and TEM measurement results showed that the composite consists of nanocubes with a homogeneous size of about 40-80 nm were uniformly covered by the grapheme sheets.Furthermore,the composite of ZnSn(OH)6/rGO was firstly used as an anode material for lithium-ion intercalation and exhibited high capacity,cycling stability and good rate performance.For example,a charge capacity of 540 mA h g-1 can still be retained after 40 cycles at 500 mA g-1.Even being cycled at a current density of 2 A g-1,the capacity of 469.4 mA h g-1 can still be obtained.Compared with the graphene wrapped Zn2SnO4 boxes,these results showed a considerable or even better electrochemical performance.The excellent electrochemical performance of ZnSn(OH)6/rGO composite greatly related to the hydroxyls groups on ZnSn(OH)6 surface,which can be combined with graphene oxides more intimate than Zn2SnO4 did.