Locust bean gum(LBG)is a typical galactomannan isolated from carob bean(Ceratonia siliqua L.)cultivated in the Mediterranean area.Due to its superior biodegradable,rheological and film-forming properties,LBG has been...Locust bean gum(LBG)is a typical galactomannan isolated from carob bean(Ceratonia siliqua L.)cultivated in the Mediterranean area.Due to its superior biodegradable,rheological and film-forming properties,LBG has been used alone or combined with other biopolymers(e.g.,polysaccharides,proteins and lipids)to develop films.Till now,different kinds of functional ingredients(e.g.,montmorillonite,bacteriocins,antibiotics,plant extract,essential oils and microbial cells)have been added into LBG-based films.Notably,the physical and functional properties of LBG-based films are affected by many factors,such as the structure of LBG,the type and content of other biopolymers and functional ingredients,and the physical treatment of film-forming solution.LBG-based films can be not only used as active packaging and edible coating in food industry but also used as wound dressings in pharmaceutical industry.For the first time,this review focuses on the recent advances in the preparation,characterization,physical and functional properties,and potential applications of LBG-based films.展开更多
Ultrasonic Assisted SILAR method （UA-SILAR） was developed and highly oriented ZnO films were deposited on the glass substrate by this novel technique. The crystallinity and microstructure of as-deposited ZnO films w...Ultrasonic Assisted SILAR method （UA-SILAR） was developed and highly oriented ZnO films were deposited on the glass substrate by this novel technique. The crystallinity and microstructure of as-deposited ZnO films were analyzed by means of XRD and SEM. Moreover, the underling deposition mechanism of ZnO films was discussed. Results show that obtained ZnO films exhibit an excellent crystallinity with the preferentioal orientation of （002） plane. The crystalline grain of films is about 40nm in size,which is supported by both the Sherrer equation and the SEM result. However, the ZnO film is composed of numerous clustered purticulates in the size of 200 to 300nm, and each particulate is the compact aggregation of smaller ZnO crystalline grains. It is .speculated that the excellent crystallinity of ZnO films may chiefly originate from the cavatition effect of the ultrasonic rinsing process.展开更多
The effect of different annealing temperatures on the structure, morphology,and optical properties of ZnO thin films prepared by the chelating sol-gel method was investigated.Zinc-oxide thin films were coated on quart...The effect of different annealing temperatures on the structure, morphology,and optical properties of ZnO thin films prepared by the chelating sol-gel method was investigated.Zinc-oxide thin films were coated on quartz glass substrates by dip coating. Zinc nitrate, absoluteethanol, and citric acid were used as precursor, solvent, and chelating agent, respectively. Theresults show that ZnO films derived from zinc-citrate have lower crystallization temperature (below400℃), and that the crystal structure is wurtzite. The films, treated over 500℃, consist ofnano-particles and show to be porous at 600℃. The particle size of the film increases with theincrease of the annealing temperature. The largest particle size is 60 nm at 600℃. The opticaltransmittances related to the annealing temperatures become 90% higher in the visible range. Thefilm shows a starting absorption at 380 nm, and the optical band-gap of the thin film (fired at500℃) is 3.25 eV and close to the intrinsic band-gap of ZnO (3.2 eV).展开更多
P-type nitrogen-doped ZnO films are prepared successfully by in-situ thermal oxidation of Zn3N2 films. The prepared films are characterized by x-ray diffraction, non-Rutherford back.scattering （non-RBS） spectroscopy...P-type nitrogen-doped ZnO films are prepared successfully by in-situ thermal oxidation of Zn3N2 films. The prepared films are characterized by x-ray diffraction, non-Rutherford back.scattering （non-RBS） spectroscopy, x- ray photoelectron spectroscopy, and photoluminescence spectrum. The results show that the Zn3N1 films start to transform to ZnO at 400℃ and the total nitrogen content decreases with the increasing annealing temperature. The p-type fihns are achieved at 500℃ with a low resistivity of 6.33Ω.cm and a high hole concentration of ＋8.82 × 10^17 cm-3, as well as a low level of carbon contamination, indicating that the substitutional nitrogen （No） is an effective acceptor in the ZnO：N film. The photoluminescence spectra show clear UV emissions and also indicate the presence of oxygen vacancy （Vo） defects in the ZnO：N films. The p-type doping mechanism is briefly discussed.展开更多
MXene presents excellent electrical conductivity,abundant surface functional groups and wonderful filmforming performance,but the lamellar layers are prone to self-stacking during film formation,which will reduce the ...MXene presents excellent electrical conductivity,abundant surface functional groups and wonderful filmforming performance,but the lamellar layers are prone to self-stacking during film formation,which will reduce the loss of electromagnetic waves,hinder ion transmission,and limit the effective load of other functional materials.The construction of the porous structure can effectively solve the self-stacking problem of MXene sheets.This article reviews the research progress of MXene porous films for electromagnetic interference(EMI)shielding,lithium/sodium ion batteries,pseudocapacitors,and biomedical science applications.It focuses on the preparation methods of MXene porous films,and discusses the pore-forming mechanism of the porous structure formed by different preparation methods and the internal relationship between the“microstructure-macroscopic performance”of the MXene porous films,points out the key scientific and technical bottlenecks that need to be solved urgently in the preparation and application of the MXene porous films.It is hoped to provide certain guidance for the design,preparation,optimization,industrial application,and development of MXene porous films.展开更多
ZnO films coated with reduced graphene oxide（RGO-ZnO） were prepared by a simple chemical approach. The graphene oxide（GO） films transferred onto ZnO films by spin coating were reduced to RGO films by two steps（ex...ZnO films coated with reduced graphene oxide（RGO-ZnO） were prepared by a simple chemical approach. The graphene oxide（GO） films transferred onto ZnO films by spin coating were reduced to RGO films by two steps（exposed to hydrazine vapor for 12 h and annealed at 600 °C）. The crystal structures, electrical and photoluminescence properties of RGO-ZnO films on quartz substrates were systematically studied. The SEM images illustrated that RGO layers have successfully been coated on the ZnO films very tightly. The PL properties of RGO-ZnO were studied. PL spectra show two sharp peaks at 390 nm and a broad visible emission around 490 nm.The resistivity of RGO-ZnO films was measured by a Hall measurement system, RGO as nanofiller considerably decrease the resistivity of ZnO films. An electrode was fabricated, using RGO-ZnO films deposited on Si substrate as active materials, for super capacitor application. By comparison of different results, we conclude that the RGOZnO composite material couples possess the properties of super capacitor.展开更多
Transparent zinc oxide（ZnO） thin films are fabricated by a simple sol-gel spin-coating technique on glass substrates with different solution concentrations（0.3-1.2 M） using zinc acetate dehydrate [Zn（CH_3COO）_2&...Transparent zinc oxide（ZnO） thin films are fabricated by a simple sol-gel spin-coating technique on glass substrates with different solution concentrations（0.3-1.2 M） using zinc acetate dehydrate [Zn（CH_3COO）_2·2H_2O] as precursor and isopropanol and monoethanolamine（MEA） as solvent and stabilizer, respectively. The molar ratio of zinc acetate dehydrate to MEA is 1.0. X-ray diffraction, ultraviolet-visible spectroscopy and photoluminescence spectroscopy are employed to investigate the effect of solution concentration on the structural and optical properties of the ZnO thin films. The obtained results of all thin films are discussed in detail and are compared with other experimental data.展开更多
基金This study was supported by Grants-in-Aid for scientific research from the National Natural Science Foundation of China(No.31571788)Natural Science Foundation of Jiangsu Province(No.BK20151310)Innovation and Entrepreneurship Training Program for College Students in Jiangsu Province.
文摘Locust bean gum(LBG)is a typical galactomannan isolated from carob bean(Ceratonia siliqua L.)cultivated in the Mediterranean area.Due to its superior biodegradable,rheological and film-forming properties,LBG has been used alone or combined with other biopolymers(e.g.,polysaccharides,proteins and lipids)to develop films.Till now,different kinds of functional ingredients(e.g.,montmorillonite,bacteriocins,antibiotics,plant extract,essential oils and microbial cells)have been added into LBG-based films.Notably,the physical and functional properties of LBG-based films are affected by many factors,such as the structure of LBG,the type and content of other biopolymers and functional ingredients,and the physical treatment of film-forming solution.LBG-based films can be not only used as active packaging and edible coating in food industry but also used as wound dressings in pharmaceutical industry.For the first time,this review focuses on the recent advances in the preparation,characterization,physical and functional properties,and potential applications of LBG-based films.
文摘Ultrasonic Assisted SILAR method （UA-SILAR） was developed and highly oriented ZnO films were deposited on the glass substrate by this novel technique. The crystallinity and microstructure of as-deposited ZnO films were analyzed by means of XRD and SEM. Moreover, the underling deposition mechanism of ZnO films was discussed. Results show that obtained ZnO films exhibit an excellent crystallinity with the preferentioal orientation of （002） plane. The crystalline grain of films is about 40nm in size,which is supported by both the Sherrer equation and the SEM result. However, the ZnO film is composed of numerous clustered purticulates in the size of 200 to 300nm, and each particulate is the compact aggregation of smaller ZnO crystalline grains. It is .speculated that the excellent crystallinity of ZnO films may chiefly originate from the cavatition effect of the ultrasonic rinsing process.
基金This work was financially supported by the Natural Science Foundation of Tianjin (No. 33802311)
文摘The effect of different annealing temperatures on the structure, morphology,and optical properties of ZnO thin films prepared by the chelating sol-gel method was investigated.Zinc-oxide thin films were coated on quartz glass substrates by dip coating. Zinc nitrate, absoluteethanol, and citric acid were used as precursor, solvent, and chelating agent, respectively. Theresults show that ZnO films derived from zinc-citrate have lower crystallization temperature (below400℃), and that the crystal structure is wurtzite. The films, treated over 500℃, consist ofnano-particles and show to be porous at 600℃. The particle size of the film increases with theincrease of the annealing temperature. The largest particle size is 60 nm at 600℃. The opticaltransmittances related to the annealing temperatures become 90% higher in the visible range. Thefilm shows a starting absorption at 380 nm, and the optical band-gap of the thin film (fired at500℃) is 3.25 eV and close to the intrinsic band-gap of ZnO (3.2 eV).
基金Supported by the National Natural Science Foundation of China under Grant Nos 10775033 and 11075038
文摘P-type nitrogen-doped ZnO films are prepared successfully by in-situ thermal oxidation of Zn3N2 films. The prepared films are characterized by x-ray diffraction, non-Rutherford back.scattering （non-RBS） spectroscopy, x- ray photoelectron spectroscopy, and photoluminescence spectrum. The results show that the Zn3N1 films start to transform to ZnO at 400℃ and the total nitrogen content decreases with the increasing annealing temperature. The p-type fihns are achieved at 500℃ with a low resistivity of 6.33Ω.cm and a high hole concentration of ＋8.82 × 10^17 cm-3, as well as a low level of carbon contamination, indicating that the substitutional nitrogen （No） is an effective acceptor in the ZnO：N film. The photoluminescence spectra show clear UV emissions and also indicate the presence of oxygen vacancy （Vo） defects in the ZnO：N films. The p-type doping mechanism is briefly discussed.
基金support and funding from the Foundation of National Natural Science Foundation of China(51903145 and 51973173)Natural Science Basic Research Plan for Distinguished Young Scholars in Shaanxi Province of China(2019JC-11)+2 种基金Natural Science Basic Research Plan in Shaanxi Province of China(2020JQ-164)the Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University(CX2021107)financially supported by Polymer Electromagnetic Functional Materials Innovation Team of Shaanxi Sanqin Scholars。
文摘MXene presents excellent electrical conductivity,abundant surface functional groups and wonderful filmforming performance,but the lamellar layers are prone to self-stacking during film formation,which will reduce the loss of electromagnetic waves,hinder ion transmission,and limit the effective load of other functional materials.The construction of the porous structure can effectively solve the self-stacking problem of MXene sheets.This article reviews the research progress of MXene porous films for electromagnetic interference(EMI)shielding,lithium/sodium ion batteries,pseudocapacitors,and biomedical science applications.It focuses on the preparation methods of MXene porous films,and discusses the pore-forming mechanism of the porous structure formed by different preparation methods and the internal relationship between the“microstructure-macroscopic performance”of the MXene porous films,points out the key scientific and technical bottlenecks that need to be solved urgently in the preparation and application of the MXene porous films.It is hoped to provide certain guidance for the design,preparation,optimization,industrial application,and development of MXene porous films.
基金supported by the National Natural Science Foundation of China(Nos.61464005,51562015)the Natural Science Foundation of Jiangxi Province(Nos.20143ACB21004,20151BAB212008,20171BAB216015)+2 种基金the Jiangxi Province Foreign Cooperation Projects,China(No.20151BDH80031)the Leader Training Object Project of Major Disciplines Academic and Technical of Jiangxi Province(No.20123BCB22002)the Key Technology R&D Program of the Jiangxi Provine of Science and Technology(No.20171BBE50053)
文摘ZnO films coated with reduced graphene oxide（RGO-ZnO） were prepared by a simple chemical approach. The graphene oxide（GO） films transferred onto ZnO films by spin coating were reduced to RGO films by two steps（exposed to hydrazine vapor for 12 h and annealed at 600 °C）. The crystal structures, electrical and photoluminescence properties of RGO-ZnO films on quartz substrates were systematically studied. The SEM images illustrated that RGO layers have successfully been coated on the ZnO films very tightly. The PL properties of RGO-ZnO were studied. PL spectra show two sharp peaks at 390 nm and a broad visible emission around 490 nm.The resistivity of RGO-ZnO films was measured by a Hall measurement system, RGO as nanofiller considerably decrease the resistivity of ZnO films. An electrode was fabricated, using RGO-ZnO films deposited on Si substrate as active materials, for super capacitor application. By comparison of different results, we conclude that the RGOZnO composite material couples possess the properties of super capacitor.
文摘Transparent zinc oxide（ZnO） thin films are fabricated by a simple sol-gel spin-coating technique on glass substrates with different solution concentrations（0.3-1.2 M） using zinc acetate dehydrate [Zn（CH_3COO）_2·2H_2O] as precursor and isopropanol and monoethanolamine（MEA） as solvent and stabilizer, respectively. The molar ratio of zinc acetate dehydrate to MEA is 1.0. X-ray diffraction, ultraviolet-visible spectroscopy and photoluminescence spectroscopy are employed to investigate the effect of solution concentration on the structural and optical properties of the ZnO thin films. The obtained results of all thin films are discussed in detail and are compared with other experimental data.
