Sn_(1−x)Er_(x)O_(2)(x=0%,8%,16%,24%)micro/nanofibers were prepared by electrospinning combined with heat treatment using erbium nitrate,stannous chloride and polyvinylpyrrolidone(PVP)as raw materials.The target produc...Sn_(1−x)Er_(x)O_(2)(x=0%,8%,16%,24%)micro/nanofibers were prepared by electrospinning combined with heat treatment using erbium nitrate,stannous chloride and polyvinylpyrrolidone(PVP)as raw materials.The target products were characterized by thermogravimetric analyzer,X-ray diffrotometer,fourier transform infrared spectrometer,scanning electron microscope,spectrophotometer and infrared emissivity tester,and the effects of Er^(3+)doping on its infrared and laser emissivity were studied.At the same time,the Sn_(1−x)Er_(x)O_(2)(x=0%,16%)doping models were constructed based on the first principles of density functional theory,and the related optoelectronic properties such as their energy band structure,density of states,reflectivity and dielectric constant were analyzed,and further explained the mechanism of Er^(3+)doping on SnO_(2)infrared emissivity and laser absorption from the point of electronic structure.The results showed that after calcination at 600℃,single rutile type SnO_(2)was formed,and the crystal structure was not changed by doping Er^(3+).The calcined products showed good fiber morphology,and the average fiber diameter was 402 nm.The infrared emissivity and resistivity of the samples both decreased first and then increased with the increase of Er^(3+)doping amount.When x=16%,the infrared emis-sivity of the sample was at least 0.71;and Er^(3+)doping can effectively reduce the reflectivity of SnO_(2)at 1.06μm and 1.55μm,when x=16%,its reflectivity at 1.06μm and 1.55μm are 50.5%and 40%,respectively,when x=24%,the reflectivity at 1.06μm and 1.55μm wavelengths are 47.3%and 42.1%,respectively.At the same time,the change of carrier concentration and electron transition before and after Er^(3+)doping were described by first-principle calculation,and the regulation mechanism of infrared emissivity and laser reflectivity was explained.This study provides a certain experimental and theoretical basis for the development of a single-type,light-weight and easily prepared infrared and laser compatible-stealth material.展开更多
A composite photocatalyst,with branch-like BiOI/Bi_(2)WO_(6) heterojunction deposited on the polyacrylonitrile micro/nano composite fiber(PAN MNCF),was prepared via two step hydrothermal method.The products are charac...A composite photocatalyst,with branch-like BiOI/Bi_(2)WO_(6) heterojunction deposited on the polyacrylonitrile micro/nano composite fiber(PAN MNCF),was prepared via two step hydrothermal method.The products are characterized by X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),photoluminescence(PL)spectra,UV-Vis diffuse reflection spectroscopy(UV-Vis DRS)and time-resolved fluorescence spectra.The PAN/BiOI/Bi_(2)WO_(6) micro/nano composite fiber(PAN/BiOI/Bi_(2)WO_(6) MNCF)showed better visible-light photocatalytic performance than PAN MNCF or BiOI/Bi_(2)WO_(6) powder,probably ascribed to the collective effect between PAN MNCF and BiOI/Bi_(2)WO_(6) heterojunction.Significantly,the PAN/BiOI/Bi_(2)WO_(6) MNCF could be easily recycled through filtration method,thus avoiding the secondary pollution.展开更多
基金supported by the Key Research and Development Program of Hebei Province(No.21351501D)A Provincial and Ministerial Scientific Research Project(LJ20212C031165)Basic Frontier Science and Technology Innovation Project of Army Engineering University of PLA(KYSZJQZL2210)。
文摘Sn_(1−x)Er_(x)O_(2)(x=0%,8%,16%,24%)micro/nanofibers were prepared by electrospinning combined with heat treatment using erbium nitrate,stannous chloride and polyvinylpyrrolidone(PVP)as raw materials.The target products were characterized by thermogravimetric analyzer,X-ray diffrotometer,fourier transform infrared spectrometer,scanning electron microscope,spectrophotometer and infrared emissivity tester,and the effects of Er^(3+)doping on its infrared and laser emissivity were studied.At the same time,the Sn_(1−x)Er_(x)O_(2)(x=0%,16%)doping models were constructed based on the first principles of density functional theory,and the related optoelectronic properties such as their energy band structure,density of states,reflectivity and dielectric constant were analyzed,and further explained the mechanism of Er^(3+)doping on SnO_(2)infrared emissivity and laser absorption from the point of electronic structure.The results showed that after calcination at 600℃,single rutile type SnO_(2)was formed,and the crystal structure was not changed by doping Er^(3+).The calcined products showed good fiber morphology,and the average fiber diameter was 402 nm.The infrared emissivity and resistivity of the samples both decreased first and then increased with the increase of Er^(3+)doping amount.When x=16%,the infrared emis-sivity of the sample was at least 0.71;and Er^(3+)doping can effectively reduce the reflectivity of SnO_(2)at 1.06μm and 1.55μm,when x=16%,its reflectivity at 1.06μm and 1.55μm are 50.5%and 40%,respectively,when x=24%,the reflectivity at 1.06μm and 1.55μm wavelengths are 47.3%and 42.1%,respectively.At the same time,the change of carrier concentration and electron transition before and after Er^(3+)doping were described by first-principle calculation,and the regulation mechanism of infrared emissivity and laser reflectivity was explained.This study provides a certain experimental and theoretical basis for the development of a single-type,light-weight and easily prepared infrared and laser compatible-stealth material.
基金This work was supported by the Natural Science Foundation of Jiangsu Province of China(No.BK20161214)the Fund of the Jiangsu Key Laboratory of Advanced Functional Polymers Design and Application,Soochow University,China.
文摘A composite photocatalyst,with branch-like BiOI/Bi_(2)WO_(6) heterojunction deposited on the polyacrylonitrile micro/nano composite fiber(PAN MNCF),was prepared via two step hydrothermal method.The products are characterized by X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),photoluminescence(PL)spectra,UV-Vis diffuse reflection spectroscopy(UV-Vis DRS)and time-resolved fluorescence spectra.The PAN/BiOI/Bi_(2)WO_(6) micro/nano composite fiber(PAN/BiOI/Bi_(2)WO_(6) MNCF)showed better visible-light photocatalytic performance than PAN MNCF or BiOI/Bi_(2)WO_(6) powder,probably ascribed to the collective effect between PAN MNCF and BiOI/Bi_(2)WO_(6) heterojunction.Significantly,the PAN/BiOI/Bi_(2)WO_(6) MNCF could be easily recycled through filtration method,thus avoiding the secondary pollution.
