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1.
ACS Appl Mater Interfaces ; 10(36): 30314-30321, 2018 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-30132662

RESUMO

Sb2S3 is a kind of new light-absorbing material possessing high stability in ambient environment, high absorption coefficient in the visible range, and abundant elemental storage. To improve the power conversion efficiency of Sb2S3-based solar cells, here we control the defect in Sb2S3 absorber films. It is found that the increase of sulfur vacancy is able to upgrade photovoltaic properties. With the increase in sulfur vacancy, the carrier concentrations are increased. This n-type doping gives rise to an upshift of the Fermi level of Sb2S3 so that the charge transport from Sb2S3 to the electron selection material becomes dynamically favorable. The introduction of ZnCl2 in film fabrication is also found to regulate the film growth for enhanced crystallinity. Finally, the photovoltaic parameters, short-circuit current density, open-circuit voltage, and the fill factor of the device based on the Sb2S3 film are all considerably enhanced, boosting the final power conversion efficiency from 5.15 to 6.35%. This efficiency is the highest value in planar heterojunction Sb2S3 solar cells and among the top values in all kinds of Sb2S3 solar cells. This research provides a fundamental understanding regarding the properties of Sb2S3 and a convenient approach for enhancing the performance of Sb2S3 solar cells.

2.
ChemSusChem ; 11(18): 3208-3214, 2018 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-30048042

RESUMO

Sb2 S3 is a new kind of photovoltaic material that is promising for practical application in solar cells owing to its suitable bandgap, earth-abundant elements, and excellent stability. Here, we report on an aqueous-solution-based approach for the synthesis of Sb2 S3 films from easily accessible Sb2 O3 as antimony source. In this reaction, 3-mercaptopropionic acid was applied as both solvent and sulfur precursor, aqueous ammonia was employed as a solvent. After simple annealing at a temperature as low as 270 °C, the spin-coated precursor solution can generate compact, flat, uniform, and well-crystallized Sb2 S3 film. Mechanistic study showed that the formation of Sb-complex with ammonium carboxylates leads to the successful dissolution of Sb2 O3 powder. A suitable annealing process was able to generate carbon-free Sb2 S3 films. Planar heterojunction solar cell based on the as-prepared Sb2 S3 film delivered a power conversion efficiency of 5.57 %, which is the highest efficiency of solution-processed planar heterojunction Sb2 S3 solar cells and a high value in all kinds of Sb2 S3 solar cells. This research provides a convenient approach for the fabrication of device-quality Sb2 S3 films, and highlights solution processing of carbon-free metal chalcogenide thin films as a suitable process for application in optoelectronic devices.

3.
ACS Appl Mater Interfaces ; 8(51): 35163-35171, 2016 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-27977117

RESUMO

The commercial applications of Mn3O4 in lithium ion batteries (LIBs) are greatly restricted because of the low electrical conductivity and poor cycling stability at high current density. To overcome these drawbacks, mesoporous Mn3O4@C networks were designed and synthesized via an improved bake-in-salt method using NaCl as the assistant salt, and without the protection of inert gas. The added NaCl plays a versatile role during the synthetic process, including the heat conducting medium, removable hard template and protective layer. Because of the homogeneous distribution of Mn3O4 nanoparticles within the carbon matrix, the as-prepared Mn3O4@C networks show excellent cycling stability in LIBs. After cycling for 950 times at a current density of 1 A g-1, the discharge capacity of the as-prepared Mn3O4@C networks is determined to be 754.4 mA h g-1, showing superior cycling stability as compared to its counterparts. The valuable and promising method, simple synthetic procedure and excellent cycling stability of the as-prepared Mn3O4@C networks makes it a promising candidate as the potential anode material for LIBs.

4.
Nanoscale Res Lett ; 11(1): 126, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26951126

RESUMO

In this report, a novel photocatalyst based on Bi2WO6/Ag2S heterostructures was prepared by a 3-mercaptopropionic acid (MPA)-assisted route at room temperature. Compared to bare Bi2WO6 and Ag2S nanoparticles, the as-formed Bi2WO6/Ag2S heterostructures exhibit enhanced photocatalytic activity for the degradation of rhodamine B (Rh B) under visible-light irradiation. This kind of enhancement in the photocatalytic activity is considered to be the synergistic effects of both the effective electron-hole separation and expansion of the light-absorption range. The pH of the solution is of vital importance to the photocatalytic activity of the as-formed Bi2WO6/Ag2S heterostructures. Under low pH value, the photosensitization process is suppressed, while under higher pH value, the photosensitization process is favored. The mechanism of the photocatalytic process was proposed by the active-species-trapping experiments, indicating that the photogenerated holes (h(+)) play a crucial role in the degradation of Rh B under visible light. The enhanced photocatalytic performance of this heterostructure makes it a promising material for the treatment of dye-containing wastewater.

5.
J Colloid Interface Sci ; 466: 388-99, 2016 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-26752434

RESUMO

Highly-efficient photocatalyst based on Bi2WO6/SnS heterostructure was prepared via a surface functionalization method using 3-mercaptopropionic (MPA) as the surface functionalizing agent. Compared to bare Bi2WO6 and SnS nanoparticles, the as-formed Bi2WO6/SnS heterostructure exhibits enhanced photocatalytic activity for the degradation of Rhodamine B (Rh B). Photoluminescence and photocurrent measurements demonstrate that the enhanced photocatalytic activity during the photocatalytic process is closely related to the enhanced electron-hole separation efficiency. The photocatalytic activity of the as-formed Bi2WO6/SnS heterostructure can be perfectly remained even after being used for five times, showing excellent durability during the photocatalytic process. The influence of pH and inorganic ions are systematically investigated. And the optimum pH for the photocatalytic process is determined to be 6. The addition of chloride ion will exert negative effect on the photodegradation process of Rh B. The mechanism of photodegradation process was investigated by exploring the quenching effects of different scavengers and the results suggest that the reactive holes play the major role in the photodegradation process of Rh B.

6.
J Colloid Interface Sci ; 432: 236-45, 2014 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-25086718

RESUMO

Controlled synthesis of well-shaped nanocrystals is of significant importance to understand the surface-related properties. Herein, hierarchical Bi2WO6 particles with different morphologies, such as flower-like and pancake-like morphologies were selectively prepared using a simple fluoride ion-assisted hydrothermal process. Morphological modulation of the samples could be easily realized by controlling the initial amount of NH4F. The effect of NH4F as well as the formation mechanism of these Bi2WO6 hierarchical structures were systematically investigated. The morphological control of the final products are proved to be a kinetic control of the reaction, which is closely related to the concentration of fluoride ion in the solution. The as-obtained hierarchical Bi2WO6 particles exhibit different visible-light-driven photo-catalytic activities for the degradation of Rhodamine-B (RhB). The differences in photo-catalytic activities among the as-obtained samples are associated the surface adsorption properties, which result from the synthetic conditions.

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