Well-aligned, long fibers composed of multi-walled carbon nanotubes (MWNTs) and polypropylene (PP) were fabricated by a conventional melt spinning technique. Scanning electron microscope (SEM) observations of the morphology revealed that both the alignment and dispersion of MWNTs in the matrix were improved. Mechanical properties of the composite fibers were studied by tensile testing and Weibull distribution, and it was found that their tensile strength was increased with addition of the carbon nanotubes. The maximum tensile strength of 61 MPa was achieved at 3w/% MWNT addition, 120% more than that of the pure PP fibers. Moreover, a unique tensile rupture characteristic was found by SEM observations, which explained the critical phenomenon that the MWNT addition affects the tensile property of the MWNT composite fibers.

Zhong Li;Zhe Ying;Min Liu;会明 成

Xinxing Tan Cailiao/New Carbon Materials

2005-6

"Graphitic" (g)-C ₃N ₄ with a layered structure has the potential of forming graphene-like nanosheets with unusual physicochemical properties due to weak van der Waals forces between layers. Herein is shown that g-C ₃N ₄ nanosheets with a thickness of around 2 nm can be easily obtained by a simple top-down strategy, namely, thermal oxidation etching of bulk g-C ₃N ₄ in air. Compared to the bulk g-C ₃N ₄, the highly anisotropic 2D-nanosheets possess a high specific surface area of 306 m ² g ^-1, a larger bandgap (by 0.2 eV), improved electron transport ability along the in-plane direction, and increased lifetime of photoexcited charge carriers because of the quantum confinement effect. As a consequence, the photocatalytic activities of g-C ₃N ₄ nanosheets have been remarkably improved in terms of •OH radical generation and photocatalytic hydrogen evolution.

Ping Niu;Lili Zhang;Gang Liu;会明 成

Advanced Functional Materials

2012-11-21

Extending the light absorption range of wide-bandgap photocatalysts into the visible light region is significant in terms of fully harvesting and converting solar light. The desirable band-to-band redshift of the absorption edge of semiconducting binary metal oxides such as prototypical photocatalyst TiO₂ by doping is long targeted but remains a challenge, up to date. Here, by taking the advantage of abundant 1D diffusion channels with rhombus-like cross-sections along the c-axis in the crystal structure of titanium oxalate hydrate to promote the entrance of nitrogen dopant species into the bulk and subsequent thermal topotactic transition in an atmosphere of gaseous ammonia, homogeneous doping of substitutional carbon/nitrogen for oxygen in the TiO₂ decahedral plates with a dominant anatase phase is obtained for the first time. The resultant TiO_2−x(CN)_y with an unusual band-to-band visible light absorption spectrum can induce photocatalytic water oxidation to release oxygen under visible light irradiation. This study provides not only a promising visible light–responsive TiO₂ photocatalyst, but also an important strategy for developing other solar-driven photocatalysts.

Tingting Wu;Ping Niu;Yongqiang Yang;Li Chang Yin;Jun Tan;Huaze Zhu;John T.S. Irvine;Lianzhou Wang;Gang Liu;会明 成

Advanced Functional Materials

2019-6-21

There is an inherent driving force to narrow the bandgap of photocatalysts towards this value. Introducing heteroatoms as a general strategy of tuning the bandgap of semiconductors has been attempted to narrow the bandgap of melon in order to extend its light absorption range. Compared to the intensive studies on oxygen vacancies, the underlying role of nitrogen vacancies in modulating optical and photocatalytic properties is rarely considered in developing nitride-based photocatalysts. On the other hand, the spatial distribution of dopants is recognized as an essential issue in modifying the electronic structure of photocatalysts. Homogeneous doping of appropriate heteroatoms throughout a whole particle is indispensable for effective bandgap narrowing, while surface doping can only result in some localized states in the bandgap.

Ping Niu;Li Chang Yin;Yong Qiang Yang;Gang Liu;会明 成

Advanced Materials

2014

The efficiency of perovskite solar cells (PSCs) has increased from around 4% to over 22% following a few years of intensive investigation. For most PSCs, organic materials such as 2,2′,7,7′-tetrakis(N,N-pdimethoxyphenylamino)-9,9′-spirobifluorene (spiro-OMeTAD) are used as the hole transporting materials (HTMs), which are thermally and chemically unstable and also expensive. Here, we explored nickel phthalocyanine (NiPc) as a stable and cost-effective HTM to replace the conventionally used spiro-OMeTAD. Because of its high carrier mobility and proper band alignments, we achieved a PCE of 12.1% on NiPc based planar device with short-circuit current density (J_sc) of 17.64 mA cm⁻², open circuit voltage (V_oc) of 0.94 V, and fill factor (FF) of 73%, outperforming the planar device based on copper phthalocyanine (CuPc) that is an outstanding representative of metal phthalocyanines (MPcs) reported. Moreover, the device with NiPc shows much improved stability compared to that based on the conventional spiro-OMeTAD as a result of NiPc's high stability. Photoluminescence (PL) and Impedance spectroscopy analysis results show that thermally deposited NiPc has good hole-extraction ability. Our results suggest that NiPc is a promising HTM for the large area, low cost and stable PSCs.

Mustafa Haider;Chao Zhen;Tingting Wu;Gang Liu;会明 成

Journal of Materials Science and Technology

2018-9

The fabrication and patterning of CNT and graphene transparent conductive films, and its use as electrodes of electroluminescent devices and organic solar cells are presented. And by using inkjet printing, all-carbon transistors are demonstrated.

会明 成

2013

Wood and bamboo ceramics are newly developed porous carbon materials from wood and bamboo impregnated with resin, and they possess some special properties and can be expected to be used as electromagnetic materials, absorbents, catalyst carrier materials, etc. In this work, the graphitization behavior of wood and bamboo ceramics was investigated by X-ray diffraction. Experimental results show that the d₀₀₂ spacing of the bamboo carbon, wood and bamboo ceramics decreased and the apparent graphite crystallite size Lc₍₀₀₂₎ increased with the increase of graphitization temperature. However, even after heat treatment at 3273 K, the d₀₀₂ and Lc₍₀₀₂₎ value was only about 0.341 and 9 nm, respectively. These results indicate that all of the bamboo carbon, wood and bamboo ceramics investigated are typical non-graphitizable carbon or hard carbon.

会明 成;Hiroyuki Endo;Toshihiro Okabe;Kouji Saito;Guo Bin Zheng

Journal of Porous Materials

1999

The research on solution processed metal halide perovskite solar cells (PSCs) as a new type of solar cells has experienced explosive growth since the first report in 2009. It is impressive that solar energy conversion efficiency has increased to over 23%. Outstanding optoelectronic properties including high absorption coefficient, high mobility, and long diffusion length of charge carriers have been revealed in the family of hybrid organic inorganic halide perovskite materials that are considered the heart of solar cells. A long-anticipated feature for solar cells that the diffusion lengths of charge carriers outstrip the active layer thickness of a device has been demonstrated in PSCs so that the efficiency of extracting photocarriers, particularly electrons at the interfaces becomes a key parameter controlling global device performance. The n-type semiconductor TiO ₂ with the merits of thermal and chemical stability, low cost, and suitable band edge positions has been regarded an ideal electron transporting layer (ETL) material in PSCs performing the function of selectively extracting photoelectrons and subsequently delivering them toward a current collector. Besides the highly concerning energy conversion efficiency of PSCs, the challenge of the current-voltage hysteresis phenomenon and instability of PSCs are also revealed to be closely related with TiO ₂ ETLs. In this review, the recent progress on strategies for modifying TiO ₂ ETLs by controlling morphology, surface modification, doping, and constructing composites to improve global performance of PSCs is reviewed. Moreover, the perspective on future development of TiO ₂ based ETLs for high performance PSCs is proposed on the basis of the comprehensive and deep understanding of TiO ₂ from the area of photocatalysis. It is anticipated that finely tailoring the features and properties of TiO ₂ ETLs will further release large room for exciting enhancements in the global performance of PSCs.

Chao Zhen;Tingting Wu;Runze Chen;Lianzhou Wang;Gang Liu;会明 成

ACS Sustainable Chemistry and Engineering

2019-3-4

The decomposition reaction of LiBH₄ with and without F anion doping was investigated by first-principles calculations. According to the calculation results, doping LiBH₄ with F anion may generate F lattice substitution in both the hydrogenated (LiBH₄) and dehydrogenated (LiH) states of the hydride, and accordingly result in a favorable thermodynamics modification, even to a level suitable for onboard H-storage application. Experimentally evidencing these theoretical predictions may pave a new way to pursue improved hydrogen storage properties of LiBH₄ and other related complex hydrides.

Lichang Yin;Ping Wang;Zhanzhao Fang;会明 成

Chemical Physics Letters

2008-1-4

Tungsten boride (WB) crystals, whose surface tends to be oxidized when exposed to air, were demonstrated to have a comparable activity to platinum as counter electrode material in dye-sensitized solar cells. The synergistic effect of both catalytically active surface layer WO_x and electronically conductive internal WB is considered to be responsible for the high activity of the WB crystals.

Jian Pan;Chao Zhen;Lianzhou Wang;Gang Liu;会明 成

Science Bulletin

2017