Sulfur Copolymer,MoS₂ And CH₃NH₃PbBr₃ One-dimensional Nanostructures:Template-directed Synthesis And Optoelectronic Performance

The unique physical/chemical properties and novel applications of one dimensional?1D?nanomaterials have been driving the exploration of synthetic approaches to control their composition,morphology and structure.Meanwhile,porous nanomaterials have attracted increasing attention owing to their superior structure properties compared with their corresponding solid counterparts.Now,the development of cheap,efficient and environment-friendly optoelectronic semiconductor nanostructures is one of the most fundmental challenges in photoelectrochemical conversion.Here,on the basis of designed synthesis of 1D and porous optoelectronic nanostructures,we have studied the photoresponse of sulfur copolymer nanowires depends on sulfur contents;we also demonstrate an effective self-template-directed strategy for the synthesis of 1D porous nanomaterials by chemical transformation of the inorganic–organic hybrid materials.By these template-directed strategies,we have successfully fabricated the sulfur copolymer organic nanowires with tunable bandgap,hierarchical nanosheet-based 2H-MoS₂ inorganic nanotubes and porous CH₃NH₃PbBr₃ perovskite organic-inorganic hybrid nanowires,achieving the coordinate control of component,morphology and nanostructure.In addition,the mechanism of the template-assisted chemical transformation,and the promising applications of these 1D nanomaterials in photoresponse are studied.The main contents of this dissertation are summarized as the following three sections:1.We report the fabrication of the poly?sulfur-random-1,3-diisopropenylbenzene??poly?S-r-DIB??copolymer nanowires using anodic aluminum oxide?AAO?membranes as templates,achieving the coordinate regulation between component and one dimensional morphology,and demonstrate that the sulfur copolymer nanowires exhibt enhanced visible-light photoresponse with preservation of the photoelectrochemical properties of elemental sulfur.In addition,the photoelectrochemical behavior of the sulfur copolymer nanowires is highly dependent on the sulfur content and size of the copolymer nanowires.Furthermore,the copolymer nanowires are used as a sulfur source and templates for fabricating metal sulfide–copolymer hybrid nanowires with potentially improved applications.2.We present a facile strategy for the synthesis of hierarchical nanosheet-based 2H-MoS₂ nanotubes by an anion-exchange reaction of the inorganic–organic hybrid Mo₃O₁₀(C₂H₁₀N₂)?ethylenediamine trimolybdate,named MoO₃–EDA herein?nanowires with L-cysteine at elevated temperature.The dissolution of ethylenediamine?EDA?in the solvent and the concentration-gradient-driven outward diffusion of MoO₃–EDA during the anion-exchange reaction were found to play a key role in the formation of the hierarchical nanosheet-based nanotubes.Furthermore,an improved photoelectrochemical performance has been achieved due to the enhanced light absorption ability,much more active sites and large mass transport of the as prepared hierarchical nanosheet-based MoS₂ nanotubes.3.We have demonstrated a facile method for the preparation of porous CH₃NH₃PbBr₃ perovskite nanowires by a self-template-directed reaction of metal ion-small organic molecule coordination nanowires at room temperature in solution.The initial formation of CH₃NH₃PbBr₃ perovskite layers on the surface of the precursor nanowires and the following dissolution of the organic component of the Pb containing precursor nanowires are considered to play an important role in the production of the porous wire-like perovskite nanostructures with preserving the 1D macrostructure.In addition,we show that the porous CH₃NH₃PbBr₃ nanowires exhibit superior photoresponse with high stability and sensitivity?photoresponse time: 0.12 s,decay time: 0.086s?.