MATERIALS RESEARCH BULLETIN
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2015
·
IF 2.288
Huanyong Li,Zhi Gu,Haiyang Zhang,Heqing Li,Li Fu
Three ZnE (E = Se, Te) single crystals were successfully grown directly from Zn-E (E = Se, Te) system with the assistance of I 2 or NH 4 Cl as the transport agents via a modified chemical vapor transport (CVT) method by avoiding the kinetics limitations of the congruent sublimation of ZnE compound. As-grown ZnE crystals exhibit different crystalline appearance due to various growth conditions. The structure, growth habit and morphologies of as-grown ZnE crystals are investigated by XRD , RO-XRD, SEM and optic microscope. ZnE crystals with NH 4 Cl transport agent look like the platelets with an interesting growth habit, while ZnE crystal with I 2 transport agent has high crystalline quality with a conical shape. Contrasting investigation between different growth results offers us an opportunity to understand the vapor-free-growth mechanism of ZnE crystals in closed-space CVT system, indicating that the free-growth habit of ZnE crystals depends on the growth parameters, which can be essentially attributed to their growth mechanism and the main vapor–solid reactions on the interfaces.
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高影响因子
ACS Applied Materials & Interfaces
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2014
·
IF 5.9
Weijun Ke,Guojia Fang,Hong Tao,Pingli Qin,Jing Wang,Hongwei Lei,Qin Liu,Xingzhong Zhao
Nickel sulfide (NiS) nanowall networks have been prepared by a novel one-step hydrothermal method on a nickel (Ni) foam substrate. The Ni foam has a high conductivity and porous structure. To our knowledge, the Ni foam is used as a conductive substrate for the dye-sensitized solar cell (DSSC) for the first time. The Ni foam is used as not only the conductive substrate but also the Ni sources of the reaction. The Ni foam supported NiS prepared by this simple hydrothermal method shows high catalytic activity for reduction of triiodide ions. The DSSC with a transparent conductive oxide (TCO)-free NiS counter electrode (CE) was herein developed and showed a higher power conversion efficiency of 8.55% than that with a TCO supported NiS CE (7.47%) and a TCO supported platinum CE (7.99%).
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PubMed
高影响因子
JOURNAL OF POWER SOURCES
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2014
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IF 5.211
Wei Zeng,Mingjun Wang,Yuan Li,Jiawei Wan,Huihui Huang,Hong Tao,David L. Carroll,Xingzhong Zhao,Dechun Zou,Guojia Fang
A semi-closed tubular light-trapping geometry is developed for dye sensitized solar cell to stabilize its power conversion efficiency (PCE) in wide light intensity range. The tubular cell consists of a dye-sensitized porous TiO 2 coated and semi-closed glass tube as photoanode, an opaque platinum metal foil wrapped on the outside of photoanode as counter electrode, and electrolyte filling in their interlayer . The open end of photoanode serves as the only light entrance. The experiment, calculation and optical studies demonstrated that the tubular geometry is beneficial to light trapping and absorption, charge transport and heat dissipation, in comparison to a planar counterpart. The PCE of tubular cell can remain about 85% of its original value even if the irradiated light intensity increases from 1 to 5 Sun, in contrast, that of planar counterpart decreases to about 60% of its original value. This feature makes the tubular cell has potential as an effective light collector in low-cost condenser solar cell system.
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高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
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2013
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IF 2.39
Pengfei Qiang,Peihua Yang,Zhiwen Liang,Yunhan Luo,Jianhui Yu,Yu Lan,Xiang Cai,Shaozao Tan,Pengyi Liu,Wenjie Mai
In this work, photoanodes with sub-micrometer cavities of different sizes and ratios were easily fabricated by burning off the polystyrene sub-micrometer spheres (PSSs) embedded in TiO 2 paste. When the original PSS in the anode was 500 nm in diameter and the ratio was 100 μl (5 vol%) PSSs solution mixed with 0.1 g TiO 2 nanoparticles, the optimized performance of the fabricated dye-sensitized solar cells (DSSCs) was remarkably ∼48% higher than that of pristine TiO 2 DSSCs without sub-micrometer cavities in control group. This great performance improvement was attributed to the ability of enhancing light scattering and maintaining low resistance with the introduction of optimized amount of sub-micrometer cavities. This general strategy should help to design and develop the future DSSCs with better performance.
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ELECTROCHIMICA ACTA
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2015
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IF 4.504
Niu Huang,Lin Chen,Hua Huang,Weiwei Sun,Shouzheng Zhang,Panpan Sun,Xiaohua Sun,Peng Xiang,Yihua Sun,Xingzhong Zhao
TiO 2 pyramids with planar-surface morphology presenting in the phases of anatase and brookite are successfully prepared, the height of which is 300-500 nm and 80-200 nm wide at the bottom. The pyramids exhibit excellent reflectance in the visible-near infrared region. When introducing the pyramids as a scattering layer covering the layer composed of TiO 2 nanoparticles , the energy conversion efficiency of dye-sensitized solar cell (DSSC) is enhanced from 6.49% to 7.25%. However, the pyramids overlayer falls from the nanoparticles underlayer easily, and the fill factor of the DSSC with the pyramids layer also become much lower. To solve the problem, we substitute TiO 2 microspheres underlayer for NP underlayer. As the tips of pyramids could be inserted into the submicron-sized gaps between the TiO 2 microspheres, the interface connection between layers of photoanode is reinforced. Current-Voltage measurement shows that the fill factor of the DSSC is much improved, and the DSSC has achieved 8.35% energy conversion efficiency. This study shows that the novel bilayer photoanode with improved light utilization and interface connection is an interesting structure for high efficiency DSSCs.
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RSC Advances
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2015
·Vol. 5
·期 45
·35635-35642
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IF 3.84
Waqar Ahmad,Liang Chu,Majid Raissan Al-bahrani,Zhichun Yang,Siliang Wang,Luying Li,Yihua Gao
In this study, we synthesized monolithic copper-oxide nanorods (CuO-NRs) and doped into active super hydrophobic acetylene black (AB) nanocrystals via a fast solvation method. The developed short-dimension assemblies are utilized as counter electrode (CE) materials for energy harvesting in dye sensitized solar cells (DSSCs). Cyclic voltammetry and electrochemical impedance spectroscopy analyses reveal that the hybrid (CuO-NRs/AB) CE displays a fast reduction rate of I3− and boosts hole-cascading as compared to those of individual AB CEs, due to the superior catalytic characteristics of CuO-NRs and the good electrical conductivity of AB. The CuO-NRs/AB based DSSCs exhibit an enhanced power conversion efficiency (PCE) of 8.05%, in contrast to AB (6.51%) and pristine Pt (6.96%) CE based DSSCs under the same experimental conditions. The CuO-NRs/AB CE, along with impressive results, has prospective applications in robust DSSCs.
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高影响因子
Nano Energy
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2013
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IF 0
Yan-Qing Zhang,De-Kun Ma,Yan-Ge Zhang,Wei Chen,Shao-Ming Huang
N-doped nanostructured carbon materials have attracted much attention because the doping can induce new unique physical and chemical properties of carbon. In this study, we report, for the first time, that N-doped carbon quantum dots (NCQDs) can combine with rutile TiO 2 and form NCQDs/TiO 2 hierarchical microspheres assembled by nanorods with enhanced photocatalytic activities under visible light irradiation. As a result, the pseudo-first-order reaction constant for the degradation of rhodamine B (RhB) on NCQDs/TiO 2 (0.11 min −1 ) is 215.7, 7.3 and 1.3 times much larger than that of NCQDs (0.00051 min −1 ), TiO 2 (0.015 min −1 ), and CQDs/TiO 2 (0.086 min −1 ), respectively. The functions of NCQDs were discussed and a new synergistic photosensitized mechanism was proposed for the degradation of RhB on the as-synthesized NCQDs/TiO 2 nanocomposites based on the experimental results. NCQDs were also applied as metal-free sensitizers in dye-sensitized solar cells (DSSCs) for the first time. A preliminary study shows that under one sun illumination (AM 1.5), the open circuit voltage and fill factor values reach 0.46 V and 43%, respectively, achieving a power conversion efficiency of 0.13% in the proof-of-concept TiO 2 -based DSSCs device. The performance of NCQDs sensitized solar cells surpasses that of N-free counterpart as well. N-doping lowered the work function of CQDs, which was responsible for enhanced photocatalytic activity of NCQDs/TiO 2 and better NCQDs sensitized TiO 2 -based solar cell performance.
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JOURNAL OF POWER SOURCES
·
2013
·
IF 4.675
Wei Zeng,Guojia Fang,Tianyang Han,Borui Li,Nishuang Liu,Dongshan Zhao,Zhiqiang Liu,Dianyuan Wang,Xingzhong Zhao,Dechun Zou
A TiO 2 -embedded NiCl 2 gel is prepared and used as growth catalyst to in situ synthesize binded, thick and porous carbon nanoparticles (CNPs) on Ti foil substrate with a simple flame synthesis method for dye sensitized solar cell (DSSC) counter electrode (CE) applications. The viscous gel catalyst can hold sufficient NiCl 2 coated on substrate to make CNP layer thick. The embedded TiO 2 can effectively separate the abundant NiCl 2 components to active the Ni catalyst for CNP growth and then make CNP layer become porous. In addition, the TiO 2 components can bind the porous CNP products to make them conductive. With an optimized TiO 2 fraction, the CE shows high catalytic ability and electrical conductivity . By applying this CNP CE for DSSC, a photovoltaic conversion efficiency of 6.6% is achieved, which exceeds 6.5% of a reference cell using costly platinum as CE. Furthermore, the CNP structure is demonstrated beneficial to carrier transport by a mass transfer model . This easy and effective preparation method may have a potential application in general nanomaterial preparation.
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JOURNAL OF POWER SOURCES
·
2013
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IF 4.675
Hong Tao,Guo-jia Fang,Wei-jun Ke,Wei Zeng,Jing Wang
In this paper, we explore a two-step treatment method to modify the Ti wires which are used as anode substrates of fiber dye sensitized solar cells (FDSSCs). A special kind of network nanoporous structure is formed on the surface of Ti wire substrates through sodium hydroxide hydrothermal reaction and titanium tetrachloride (TiCl 4 ) assistant treatment. Nanoporous structures with different sizes are in-situ grown on the Ti wire substrates by changing the hydrothermal reaction condition. Then, TiO 2 network nanoporous structures with branch-like nano-structure or 2D nanoflakes are obtained after TiCl 4 treatment. The effects of these network nanoporous structures on the FDSSC performances are investigated intensively. It is found that these special network nanoporous structures between TiO 2 nanoparticle active layer and Ti wire substrate are beneficial to the connection of the nanoparticle layer and fiber-shaped substrate, thus improving the electron transport rate and prolonging electron lifetime . As a result, the power conversion efficiency of this parallel assembled FDSSC increases to 4.64% from 2.56% after this two-step treatment.
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高影响因子
Journal of Materials Chemistry A
·
2015
·Vol. 4
·期 2
·466-477
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IF 7.443
Bo Li,Enyan Guo,Chengxiang Wang,Longwei Yin
We developed a facile strategy for the fabrication of uniform Au inlaid Zn2SnO4/SnO2 hollow rounded cubes with an adjustable Au loading content using ZnSn(OH)6 as the precursor, chloroauric acid as the Au source and ascorbic acid as the reducing agent. The Au inlaid Zn2SnO4/SnO2 hollow rounded cubes show enhanced light absorption ability and reduced recombination rate of photogenerated electron–hole pairs compared with pure Zn2SnO4/SnO2. The hollow rounded cube structured Au–Zn2SnO4/SnO2 sample displays a high surface area and high dye adsorption ability. As photoanodes for DSSCs, the Au–Zn2SnO4/SnO2 hollow rounded cubes demonstrate a greatly enhanced Jsc and an improved power conversion efficiency of up to 2.04%, almost 73% higher compared to the photovoltaic conversion efficiency of pure Zn2SnO4/SnO2 based DSSCs. The greatly improved power conversion efficiency of DSSCs based on the Au inlaid Zn2SnO4/SnO2 photoanode can be attributed to the following three factors. Firstly, the localized surface plasmon resonance of Au nanoparticles plays a crucial role in the enhancement of visible light absorption. Secondly, the potential barrier on the Zn2SnO4/SnO2 surface caused by Au nanoparticles can suppress electron–hole recombination, diminish the loss of electrons during the transfer process and improve the photocurrent density. Thirdly, the enhanced photovoltaic performance can also be attributed to the unique structural characteristics of hollow rounded cubes.
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ACS Sustainable Chemistry & Engineering
·
2015
·
IF 4.642
Shanlong Chen,Aichun Xu,Jie Tao,Haijun Tao,Yizhou Shen,Lumin Zhu,Jiajia Jiang,Tao Wang,Lei Pan
A novel in-situ and green method with the combination of TiCl4 pretreatment and solvothermal growth was proposed to prepare the Pt-free Cu2ZnSnS4 (CZTS) counter electrodes (CEs) on FTO substrate. It was found that TiCl4 pretreatment toward the substrates was crucial to a high quality and high efficiency CZTS film, which consists of nanosheet and nanoparticle structure. The highly crystallized nanosheets were assembled from kesterite structure CZTS nanocrystals, with an average diameter of 10–30 nm. The detailed morphology, crystal structure, and composition of the CZTS nanostructures were characterized by SEM, TEM, SAED, XRD, Raman, and EDS analysis, respectively. Electrocatalytic abilities of the films toward I–/I3– were verified through cyclic voltammograms (CV), electrochemical impedance spectroscopy (EIS), and Tafel polarization measurements. A maximum power conversion efficiency of 5.65% was achieved for a cell with CZTS 3, under 100 mW/cm2, which was higher than that of a cell with a commercial Pt counter electrode (4.96%). This high efficiency was mainly attributed to the good bonding strength between CZTS films and FTO substrate (RS = 4.41 Ω cm2), and higher electron-transfer process at the electrolyte/CE interface (high JSC), along with superior electrochemical catalytic ability (RCt = 2.40 Ω cm2). The in-situ prepared CZTS CEs are proven to be suitable for high efficiency Pt-free dye-sensitized solar cells (DSSCs), leading to significantly decrease of the cell cost and simplification of preparation process.
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ACS Applied Materials & Interfaces
·
2014
·
IF 5.9
Lu Han,Ye Feng Wang,Jing Hui Zeng
Thiaozole/benzothiaozole-based dicationic conductors were synthesized and applied as solid-state electrolyte in dye-sensitized solar cells (DSSCs). X-ray diffraction, scanning electron microscopy, thermal gravimetric analysis, steady-state voltammogram, photocurrent intensity–photovoltage test, and electrochemical impedance spectroscopy are used to characterize the materials and the mechanism of the cell performance. Compared to the traditional monocationic crystals, the dicationic crystals have a larger size and can provide more opportunities to fine-tune their physical/chemical properties. As a consequence, this solid-state electrolyte-based DSSC achieved photoelectric conversion efficiency of 7.90% under full air-mass (AM 1.5) sunlight (100 mW·cm–2).
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高影响因子
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