Co-reporter:Wen Li;Xiuxun Han;Yun Zhao;Shengrong Yang
Journal of Materials Science: Materials in Electronics 2016 Volume 27( Issue 11) pp:11188-11191
Publication Date(Web):2016 November
DOI:10.1007/s10854-016-5238-2
Molybdenum (Mo) is commonly used as the back contact material complying well with the formation of an ohmic contact for chalcogenide thin film solar cells. However, the easy formation of an over-thick MoSe2 layer between the Cu2ZnSn(S,Se)4 absorber and Mo back contact significantly deteriorates the device performance. To overcome the degradation, the effects of thermal treatment on Mo layers have been investigated in this paper. It was found that pre-annealing Mo back contacts is effective to control the growth of interfacial MoSe2 layer during selenization. Moreover, the thickness of MoSe2 layer could be conveniently tailored by simply varying the pre-annealing temperature. The work provides direct proof that the appearance of a thin MoO2 layer on the top of annealed Mo film indeed acts as a temporary barrier to block the over-selenization of Mo back contact.
Co-reporter:Wen Li, Xiuxun Han, Yun Zhao, Yonge Gu, Shengrong Yang, Tooru Tanaka
Journal of Power Sources 2015 Volume 294() pp:603-608
Publication Date(Web):30 October 2015
DOI:10.1016/j.jpowsour.2015.06.103
•Cu2ZnSn(SxSe1−x)4 alloy nanocrystals are synthesized by solvothermal method.•The CZTSSe nanocrystals have tunable composition and band gaps.•The phase structure of nanocrystals could be changed by varying the S/Se ratio.Cu2ZnSn(SxSe1−x)4 (CZTSSe) nanocrystals (NCs) are synthesized via a one-pot solvothermal method under the mild reaction condition. By varying the S/Se ratio in the solution, the chalcogen composition of CZTSSe NCs can be well controlled over the whole range, leading to a tunable bandgap from 1.11 to 1.49 eV. Furthermore, it reveals that the S/Se ratio of anionic precursors has a dramatic effect on the phase structure of CZTSSe NCs. When the S/(S + Se) ratio (x) is higher than 0.5, wurtzite (WZ)-derived structure is the dominant phase; on the contrary, the zinc blende (ZB)-derived structure overwhelms the former as x gradually reduces from 0.5 to 0. Our findings thus suggest a novel and facile method to obtain CZTSSe NCs with metastable WZ phase, which is distinguished from previously reported routes based on carefully choosing organic solvents and/or capping ligands. In addition, the obtained CZTSSe NCs are readily dispersed in low boiling point and low toxicity solvent to form homogeneous and stable NCs ink. The photocurrent response measurement on the CZTSSe NCs films demonstrates its potential as a low-cost, high-reproducibility and high-yield NC preparing approach towards efficient CZTSSe solar cells.
Co-reporter:Wen Li, Xiuxun Han, Yun Zhao, Liang Liu, Jinqing Wang, Shengrong Yang, Tooru Tanaka
Materials Letters 2014 Volume 125() pp:167-170
Publication Date(Web):15 June 2014
DOI:10.1016/j.matlet.2014.03.159
•The Cu2SnS3@ZnS nanoparticles were prepared via a two-step hydrothermal route.•Cu2ZnSnS4 was achieved by annealing the Cu2SnS3@ZnS core–shell nanoparticles.•This approach is cost-effective and would be scaled up for industrial production.A facile and low-cost approach was developed to prepare high quality quaternary Cu2ZnSnS4(CZTS) alloys through the thermal treating of the core–shell Cu2SnS3@ZnS nanoparticles. The synthesis process of the core–shell structure involves a simple two-step hydrothermal route that starts from the well-dispersed ternary Cu2SnS3 core with the introduction of poly(vinylpyrrolidone) (PVP) in the reaction solution, and ended by the coated binary ZnS shell upon the adsorption of citrate groups onto the preformed cores. X-ray diffraction, Raman spectrum and UV–vis absorption spectrum confirmed the single-phase formation and the proper bandgap of 1.51 eV for the CZTS alloys. This effective hydrothermal method can be readily applied for industrial production.
Co-reporter:Li-Bin Zhang, Jin-Qing Wang, Hong-Gang Wang, Ye Xu, Zhao-Feng Wang, Zhang-Peng Li, Yong-Juan Mi, Sheng-Rong Yang
Composites Part A: Applied Science and Manufacturing 2012 Volume 43(Issue 9) pp:1537-1545
Publication Date(Web):September 2012
DOI:10.1016/j.compositesa.2012.03.026
Graphene oxide sheets with isocyanate functional groups (GONCO) were firstly synthesized and functionalized graphene/polyimide (FGS/PI) nanocomposites were subsequently prepared by typical solution casting and thermal imidization. The chemical changes of GONCO during the preparation of FGS/PI nanocomposites were carefully characterized by Fourier transfer infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analyses. As a result, the morphology analysis indicated that the FGS were dispersed in the PI matrix and were aligned more orderly with increasing the FGS contents. The tensile strength and the modulus of FGS/PI nanocomposites were significantly increased by 60% with a small quantity of 0.75 wt% FGS incorporated and decreased beyond that dosage. Moreover, the thermogravimetric analysis (TGA) results revealed that the thermal stability of PI was slightly improved by the incorporation of FGS.
Co-reporter:Penghua Yan, Jinqing Wang, Lin Wang, Bin Liu, Ziqiang Lei, Shengrong Yang
Applied Surface Science 2011 Volume 257(Issue 11) pp:4849-4855
Publication Date(Web):15 March 2011
DOI:10.1016/j.apsusc.2010.12.111
Abstract
In this work, polydopamine coated carbon nanotubes were firstly prepared by a simple and feasible route. Then, for comparison, the in vitro bioactivity and cytocompatibility of the carbon nanotubes and the polydopamine coated carbon nanotubes were assessed by immersion study in simulated body fluids and 3-(4,5-dimethyldiazol-2-yl)-2,5-diphenyl tetrazolium bromide test using osteoblast cells (MC3T3-E1), respectively. As a result, it has been demonstrated that the introduction of polydopamine coating can greatly enhance the bioactivity and promote cell proliferation of the carbon nanotubes. The improvement of bioactive behavior is attributed to the good combination of catecholamines structure of the polydopamine and the structural advantages of carbon nanotubes as a framework material. It is anticipated that the polydopamine coated carbon nanotubes would find potential applications in bone tissue engineering and other biomedical areas.
Co-reporter:Sheng Liu, Jinqing Wang, Dong Zhang, Puliang Zhang, Junfei Ou, Bin Liu, Shengrong Yang
Applied Surface Science 2010 Volume 256(Issue 11) pp:3427-3431
Publication Date(Web):15 March 2010
DOI:10.1016/j.apsusc.2009.12.046
Abstract
Considering for the potential application in tissue engineering, polyaniline (PANi) film was fabricated via a two-step route: a self-assembled monolayer of C6H5NHC3H6Si(OMe)3 was firstly formed on the single-crystal Si substrate; the conducting PANi film was then prepared through electroless surface polymerization of the aniline molecules on the aniline monolayer-bearing silane surface in an acidic aqueous solution. The formation of PANi film on Si surface was confirmed by characterizations of X-ray photoelectron spectroscope (XPS) and specular reflectance Fourier transform infrared (SR-FTIR) spectrum, etc. At last, the proliferation behaviors of PC-12 cells on the PANi film surface were studied by the [3-(4,5-dimethyldiazol-2-yl)-2,5-diphenyl tetrazolium bromide] (MTT) colorimetric assays, acridine orange fluorometric staining, and scanning electron microscope (SEM) observation, etc. The results demonstrate that the as-prepared PANi film provides high ability for cell proliferation, exhibiting promising potentials as surface coating to cultivate neuronal cells for applications in the tissue engineering.
Co-reporter:Junfei Ou, Jinqing Wang, Jinfang Zhou, Sheng Liu, Yuanlie Yu, Xianjuan Pang, Shengrong Yang
Progress in Organic Coatings 2010 Volume 68(Issue 3) pp:244-247
Publication Date(Web):July 2010
DOI:10.1016/j.porgcoat.2010.01.004
Metal aluminum (Al) is being widely used in industry and can be easily corroded in severe conditions. Recently, dopamine has been demonstrated to be an effective adhesive molecular that can be attached to virtually all material surfaces to form stable polydopamine coating (PDAc), exhibiting promising prospects in many fields. In this work, to improve the anti-corrosion performance of Al sheet, a novel polydopamine-based 3-layer organic coating has been constructed by a multi-step self-assembly technique for the first time. In brief, a self-assembled monolayer of (3-mercaptopropyl)trimethoxysilane (coded as MPTS-SAM) was firstly prepared for enhancing the adhesion between the PDAc and the Al substrate. Subsequently, a PDAc was assembled onto the Al substrate by a simple immersion into the dopamine hydrochloride solution at a pH of 8.5. At last, a layer of tetradecanoyl chloride was grafted onto the PDAc surface through amidation, which could apparently slow down the water diffusion to the interface of PDAc and Al for its prominent hydrophobicity. Corrosion resistance of the synthesized coating in NaCl solution was evaluated by potentiodynamic polarization test and electrochemical impedance spectroscopy (EIS) measurement, respectively. As results show, PDAc on bare Al can protect the substrate from corrosion to a certain extent. Significantly, after being mediated by MPTS-SAM underlayer and covered by tetradecanoyl chloride outer layer, the anti-corrosion capability of the coating has been improved markedly.
Co-reporter:Liping Ning, Lingqi Jian, Shengrong Yang, Jinqing Wang, Junfang Ren, Jianmin Wang
Tribology International 2010 Volume 43(Issue 3) pp:568-576
Publication Date(Web):March 2010
DOI:10.1016/j.triboint.2009.09.005
The triboelectrification electrostatic potential (TEP) of neat MC nylon and MC nylon composites were investigated under dry sliding and dry rolling, respectively, and the effect of carbon black (CB) and mechanisms of anti-triboelectrification of composites were studied. The incorporation of CB with proper fractions made considerable contributions to reduce and stabilize the TEP and to control the electrical resistivity of composites. The TEP of neat MC nylon is easily influenced by friction operating parameters, while the external conditions almost have no influence on the TEP of composites. It is the conductive paths that play the dominant role in composites.
Co-reporter:Penghua Yan, Jinqing Wang, Sheng Liu, Junfei Ou, Ziqiang Lei, Shengrong Yang
Journal of Non-Crystalline Solids 2010 Volume 356(28–30) pp:1514-1518
Publication Date(Web):15 June 2010
DOI:10.1016/j.jnoncrysol.2010.05.058
Mesoporous bioactive glass (MBG) of CaO–SiO2–P2O5 was synthesized using nonionic block copolymer (EO20PO70EO20, P123) and acetic anhydride as the template and catalyst, respectively. It was inferred that acetic anhydride could accelerate the hydrolysis of tetraethyl orthosilicate and the obtained by-product of acetic acid was harmless to the environment. The TEM analysis indicated that the synthesized MBG had two-dimensional (2D) hexagonal mesostructures, and the measured BET surface area, pore volume and pore diameter were 499 m2/g, 0.70 cm3/g and 6.1 nm, respectively. Moreover, the synthesized MBG showed an excellent bioactivity in vitro as assessed by immersion studies in simulated body fluid (SBF). In a word, this work presents a simple and environment friendly route for synthesizing MBG by use of acetic anhydride as the catalyst and would find potential applications in tissue engineering and other fields.
Co-reporter:Caihong Tao;Shengrong Yang;Junyan Zhang
Chinese Journal of Chemistry 2010 Volume 28( Issue 2) pp:325-328
Publication Date(Web):
DOI:10.1002/cjoc.201090075
Abstract
The protein nanotubes fabricated by a layer-by-layer deposition method using the porous alumina membrane as the template were described. The combination of the template method and the layer-by-layer assembly technique for the fabrication of protein nanotubes presented simplicity and versatility. The nanotubes composed of two kinds of proteins (bovine serum albumin and hemoglobin lyophilized bovine erythrocytes) with different sizes could be synthesized through this method. The outside diameter of the obtained nanotubes was determined by the diameter of the pores of the template. And the wall thickness of the protein nanotubes increased with the increase of the number of protein layers that made up of the walls of nanotubes. Such biodegradable nanotubes with good biocompatibility should be useful for in vivo applications.
Co-reporter:Junfei Ou, Jinqing Wang, Dong Zhang, Puliang Zhang, Sheng Liu, Penghua Yan, Bin Liu, Shengrong Yang
Colloids and Surfaces B: Biointerfaces 2010 Volume 76(Issue 1) pp:123-127
Publication Date(Web):1 March 2010
DOI:10.1016/j.colsurfb.2009.10.024
Titanium oxide (TiO2) films were successfully deposited onto the polymer substrates of polytetrafluoroethylene (PTFE), polyethylene (PE), and polyethylene terephthalate (PET), which were pre-modified with polydopamine coating (polydopamine and its coating are coded as PDA and PDAc, respectively), by a simple liquid phase deposition (LPD) process. The morphology and chemical state of the obtained TiO2 films were characterized by field emission scanning electron microscope (FE-SEM) and X-ray photoelectron spectroscopy (XPS), respectively. Subsequently, the biocompatibility of the samples was investigated by 3-(4,5-dimethyldiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) colorimetric assay and acridine orange staining of MC-3T3 osteoblast cells, and the results demonstrated that the fabricated TiO2 films could markedly improve the in vitro cytocompatibility. So, the presented route is anticipated to be a promising surface modification methodology to improve the practical outcome of the implanted materials for its versatility and validity.
Co-reporter:Y.M. Chen, Z.X. Zeng, S.R. Yang, J.Y. Zhang
Diamond and Related Materials 2009 Volume 18(Issue 1) pp:20-26
Publication Date(Web):January 2009
DOI:10.1016/j.diamond.2008.07.023
Boron carbon nitride films were deposited onto silicon substrates by medium frequency magnetron sputtering from graphite and boron targets with Ar and N2 as feedstock. The three elements of B, C and N were bonded to each other and an atomic-level hybridized B–C–N had been formed in the films. The tribological performances of the boron carbon nitride film with 1-butyl, 3-methylimidazolium tetrafluoroborate ionic liquid as lubricant and the electrochemical corrosive behaviors of the BCN film were investigated. The boron carbon nitride film demonstrated excellent tribological properties and corrosion resistance as compared with diamond like carbon film. An extensive discussion of the effect of film intrinsically structure on both lubrication and corrosion under ionic liquid condition is given. In addition, the interrelation between the tribological properties and corrosion resistance is illustrated.
Co-reporter:Lingqi Jian;Liping Ning;Shengrong Yang;Jianmin Wang;Minqi Hua
Tribology Letters 2009 Volume 36( Issue 3) pp:
Publication Date(Web):2009 December
DOI:10.1007/s11249-009-9473-z
The triboelectrification electrostatic potential of MC nylon 6 and its influence factors have not been investigated to date. Here, we report on our study of the interaction of tribological behaviors and triboelectrification electrostatic potential for the prevention or application of triboelectrification. The equipment we used to polymerize insulation materials and for instantaneously monitoring the dynamic variations of triboelectrification electrostatic potential, friction coefficient, and temperature at the tribo-interface was self-designed. The dynamic variations in the triboelectrification electrostatic potential of the polymer insulation materials under dry sliding were investigated using this equipment. An obvious influence on magnitude and change tendency of the triboelectrification electrostatic potential of MC nylon 6 could be produced only when the combined action of load (P) and speed (V) made PV values reach a certain degree. After MC nylon 6 rubbing against the bearing steel, the triboelectrification electrostatic potential of MC nylon 6 was not constant, and it could even abruptly drop from hundreds of volts to 0, especially under severe sliding conditions. A positive charge existed on the tribo-surface of MC nylon 6 and a negative charge existed on the tribo-surface of the counterpart steel. During the severe wear process, the experimental conditions, wear rate, the formation of transfer film, and the fraction of film on the counterpart as well as frictional heat were the most significant interaction effects on the abrupt change in the triboelectrification electrostatic potential among all factors studied. The interaction of tribological behaviors and triboelectrification electrostatic potential was clearly not a simple physical mechanism, which might be influenced by the external conditions and internal integration.
Co-reporter:Junfei Ou, Jinqing Wang, Sheng Liu, Jinfang Zhou and Shengrong Yang
The Journal of Physical Chemistry C 2009 Volume 113(Issue 47) pp:20429-20434
Publication Date(Web):November 2, 2009
DOI:10.1021/jp9073416
A novel 3-layer organic film was fabricated on silicon wafer with a polydopamine coating (coded as PDAc) as the interlayer by a multistep self-assembly process. The formation and structure of the films were analyzed by means of ellipsometric thickness measurement, water contact angle measurement, and attenuated total reflection-Fourier transform infrared spectrometry (ATR-FTIR). Meanwhile, an atomic force microscope (AFM) characterization was performed to evaluate the adhesive and microtribological behaviors of the 3-layer film, and a ball-on-plate tribometer was used to test macrotribological performance. As results show, the as-prepared 3-layer film possessed the excellent tribological properties characterized by lower friction and higher antiwear ability, which was ascribed to the special chemical structure of the film, i.e., the strong adhesion of the film to the silicon wafer, the chemical bonding between the adjacent layers, the cross-linked structure of the PDAc interlayer, and the hydrophobicity, high flexibility, and high elasticity of the stearoyl chloride (STC) outer layer. Hopefully, the present work provides a feasible route to construct a multilayer film with excellent structural stability and tribological behavior. The titled multilayer film might find potential applications in boundary lubrication and many other areas.
Co-reporter:Gang Chen, Junyan Zhang, Shengrong Yang
Electrochemistry Communications 2008 Volume 10(Issue 1) pp:7-11
Publication Date(Web):January 2008
DOI:10.1016/j.elecom.2007.10.006
A novel electrochemical route for the preparation of hydrophobic fluorinated amorphous carbon (a-C:F) films with nanostructured surfaces on single crystal silicon substrate was reported. The films were investigated in terms of the surface morphology, chemical composition, microstructure and hydrophobic behavior. The results showed that a highly uniform and densely packed bamboo shoot-like nanostructure was obtained without any use of template. The incorporation of fluorine presented mainly in the forms of CF2 chains and CCFx (x = 1, 2) in the films. Sessile drop water contact angle measurements showed that the contact angle of a-C:F films deposited by electrochemical route was about 145°, which can be attributed to the lower surface energy of CFx groups and higher diffusion resistance of the special nanostructured surface to water. Moreover, the related growth mechanism of the resulting films in liquid-phase electrodeposition is discussed as well.
Co-reporter:Chengbing Wang, Shengrong Yang, Junyan Zhang
Journal of Non-Crystalline Solids 2008 Volume 354(15–16) pp:1608-1614
Publication Date(Web):15 March 2008
DOI:10.1016/j.jnoncrysol.2007.10.031
The growth and microstructure of hydrogenated carbon nitride a-CNx:H (0 ⩽ x ⩽ 0.10) films deposited by PECVD have been studied. Upon the analysis of FTIR spectra, Raman spectra and XPS, it is concluded that π doping could take place even at a very low percentage of nitrogen, which favors the formation of sp2 carbon clusters. The C 1s peak shifts toward higher binding energy while the N 1s peak remains constant as the nitrogen content in the film increases, which can be considered as a result of the chemical shifts on charge transfer due to the strong electronegativity of the N atom. 3D profile measurements show that there were a great number of particles formed when nitrogen is incorporated in to the films and the particles coalescence when the nitrogen content increases due to enhanced surface diffusion. The stress of the films converts from compressive to tensile stress gradually with increased N content. The elimination of grain boundaries and annihilation of excess vacancies, due to columnar structure increasing by diffusion leads to volume shrinkage of the film, thus causing tensile stress. These analyses were fairly consistent to help understand the effects of nitrogen in hydrogenated carbon films.
Co-reporter:Chengbing Wang, Shengrong Yang, Junyan Zhang
Diamond and Related Materials 2008 Volume 17(Issue 2) pp:174-179
Publication Date(Web):February 2008
DOI:10.1016/j.diamond.2007.11.013
Two series of a-C(N):H films, with diamond-like character and graphite-like character respectively, are prepared. Without N incorporation, the two kinds of films have very close IR bands in the range of 1000–1800 cm− 1. However, the difference in IR activity of the two series films became dramatical as N was introduced into both kinds of carbon films, which is attributed to purely electronic effect, the electronegativity of N. The N incorporated in carbon films is able to induce bond dipole of CC bonds in sp2 graphite cluster, leading to a degree of dipoles for all the aromatic sp2 CC bonds, a permanent electric dipole effect arises and this could lead to the increase in IR activity of the sp2 clusters. As the N content exceeds 20 at.% in the carbon films, strong conjugation of C≡N bonds with aromatic graphite rings can induce conjugated π bond dipole too.
Co-reporter:Gang Chen, Junyan Zhang, Shengrong Yang
Electrochemistry Communications 2007 Volume 9(Issue 5) pp:1053-1056
Publication Date(Web):May 2007
DOI:10.1016/j.elecom.2006.12.019
In this communication we report a novel electrochemical route for the preparation of Au nanoparticles incorporated a-C:H films on single crystal silicon substrates by choosing methanol as carbon source and Au nanoparticles as dopant. The morphology, composition and structure of the film have been investigated and the results show that the film obtained in our method is a hydrogenated diamond-like carbon film and zero-valence Au nanoparticles are stable and well-dispersed into the amorphous carbon matrix with unchanged size. It is simplified to achieve the co-deposition of carbon and metal by using metal nanoparticles rather than the metal salt solution as the dopant. The incorporation of Au nanoparticles in the carbon matrix can drastically decrease the resistivity and convert a-C:H films from insulator to semiconductor easily. The growth mechanisms of the Au-DLC films are also discussed.
Co-reporter:Xiaohong Liu, Jinqing Wang, Junyan Zhang, Bin Liu, Jinfang Zhou, Shengrong Yang
Thin Solid Films 2007 Volume 515(20–21) pp:7870-7875
Publication Date(Web):31 July 2007
DOI:10.1016/j.tsf.2007.03.054
Multilayer nanocomposite films composed of negative charged Ag nanosized particles and cationic polyallylamine hydrochloride (PAH) molecules were fabricated on polymer modified single-crystal silicon and flat glass slides by a layer-by-layer (LBL) molecular self-assembly technique. The X-ray photoelectron spectroscopy analysis showed that the formed Ag particles successfully absorbed onto the positively charged surfaces. The atomic force microscopy image of a two-cycle Ag/PAH bilayer film showed that no surface damage or defects existed on the thin-films surface. The Ag particles were densely and homogeneously distributed on the surface and relatively uniform in size. Goniometry was employed to verify the assembly process and the water contact angles oscillated regularly, depending on the composition of the outermost layer. By using the LBL deposition technique, a molecular-level ordered multilayer film with the thickness up to 40 layers (20 bilayers) was obtained. Results from UV–vis spectroscopy and ellipsometry measurements revealed that the self-assembly of the Ag/PAH multilayer film was well quantitative and reproducible. Thus we can conclude that the consecutive LBL deposition technique is a feasible and effective way to produce multilayer film and control the surface properties.
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