Tailored Growth,structure Regulation And Optoelectrical Performance Of One-dimensional CsPbI₃ Nanomaterials

One-dimensional CsPbI₃ semiconductor nanomaterials have excellent photoelectric characteristics,such as high absorption coefficient,long carrier diffusion distance,high carrier mobility,long carrier lifetime,and one-dimensional conductive channel limit the active area of carriers and shortening the carrier transport distance,make it has potential application prospects in the field of high-efficiency optoelectronic devices.This thesis focuses on one-dimensional CsPbI₃novel nanomaterials,and carries out some exploratory research work on their growth,structural regulation,and photoelectric properties.Synthesizing the work of this thesis,the research results are as follows:(1)Preparation and growth mechanism of one-dimensional CsPbI₃ nanobelts are explored.The preparation of one-dimensional CsPbI₃ nanobelts and the wide range of length-diameter ratio adjustment are reported for the first time by solvothermal method.The results have shown that the prepared nanobelts have a?-phase single crystal structure and grow along the[100]direction.By changing the amount of cesium carbonate precursor added,the width and thickness of the nanobelts can be regulated,and the width to thickness ratio can be adjusted from 1 to 6.35.The growth mechanism of nanobelts is mainly attributed to the surfactant-assisted,seed-mediated anisotropic growth mechanism.(2)The electrical properties of one-dimensional cesium lead iodine nanobelts are studied.Studies show that the single-crystal CsPbI₃ nanobelts have an energy band gap of?2.7 e V,a work function(?)of?3.56 e V,and valence band maximum(VBM)and conduction band minimum(CBM)vs.vacuum level of?-4.86 and?-2.16 e V,respectively.The detection and analysis of the electron emission characteristics of CsPbI₃ nanobelts show that the electron emission of nanobelts obeys the conventional field emission mechanism.While the distance between the surface of emitter and the anode is fixed at 900?m,the turn-on field(E_to)and the field enhancement factor(?_ef)of CsPbI₃ nanobelts are?2.62 V�?m^-1 and?3553,respectively,and the maximum current densities can be up to?560?A�cm^-2,which is better than the reported performance of organic-inorganic perovskite-based and most inorganic nano-field emission cathodes.(3)Photoelectric performance of Sn-doped CsPbI₃ one-dimensional nanomaterials is studied.The preparation of single-crystal Sn-doped CsPbI₃ nanobelts is realized by a solvothermal route,and its VBM and CBM vs.vacuum level are ca.?-4.37 and?-1.94 e V,respectively,with an energy band gap of?2.43 e V.The photoelectric detection performance research shows that the responsivity,external quantum efficiency and detectivity of the the Sn-doped CsPbI₃ nanobelt photodetector can reach 1.18�10³ A�W^-1,3.63�10⁵%and 6.43�10¹³ Jones,respectively,showing excellent photoelectric detection characteristics.(4)Photoelectric properties of CsPbI₃ nanotubes are studied.Single-crystal CsPbI₃ nanotubes are synthesized by solvothermal route.The photodetectors based on CsPbI₃ nanotubes have a responsivity,detectivity and external quantum efficiency of1.84�10³ A�W^-1,9.99�10¹³ Jones and 5.65�10⁵%,respectively,and its detectivity exceeds the highest reported value of ABX₃-based(A=MA,FA,Cs;B=Pb;X=Cl,Br,I)photodetectors.The enhancement of its photoelectric detection performance is mainly due to the light trapping effect of the unique cavity structure of the nanotubes.