Disclosed is an apparatus for preparing a large-area perovskite thin film. The apparatus comprises a vacuum chamber (1), with a substrate heater (2) for having a substrate placed thereon being disposed in the vacuum chamber. A first evaporation housing (3) and a second evaporation housing (4) are disposed in the vacuum chamber and under the substrate heater, wherein the first evaporation housing is nested on an upper end of the second evaporation housing, and a baffle plate (7) is disposed between the first evaporation housing and the substrate heater; a first heater (5) is disposed on the bottom of the first evaporation housing, and the first evaporation housing is connected to a first carrier gas pipeline (31), with the first carrier gas pipeline being in communication with an external carrier gas source; and a second heater (6) is disposed on the bottom of the second evaporation housing, and the second evaporation housing is connected to a second carrier gas pipeline (41), with the second carrier gas pipeline being in communication with the external carrier gas source. By means of a carrier gas, the apparatus sprays a reacting species onto the substrate via a spray head, so that a perovskite thin film is formed by means of a reaction, and the evenness of the large-area deposition of the perovskite thin film is greatly improved.
A silicon wafer horizontal growth device and method, the silicon wafer horizontal growth device comprising an outer shell forming a cavity; a crucible (10), positioned in the cavity and having a melt region (1), an overflow opening (2), a first overflow surface (3), and a second overflow surface (4); a feed assembly, used for introducing silicon raw material into the melt region, and having an adjustable feed rate; a heating assembly, comprising two movable heating devices (11, 12) arranged at a certain distance on the upper and lower side of the crucible (10); a thermal insulation assembly, used for maintaining the temperature of the cavity; a gas flow assembly, comprising a jet device (15), a gas guiding graphite member (16), a quartz suction pipe (13), and a quartz cooling pipe (14), the jet device (15) being positioned above the second overflow surface (4), the gas guiding graphite member (16) being arranged at the bottom of the crucible (10), the quartz cooling pipe (14) being sleeved over the quartz suction pipe (13), and the quartz suction pipe (13) and the gas guiding graphite member (16) being interconnected; and a thermal insulation baffle plate (17), positioned above the second overflow surface (4), and used for isolating the heating assembly from the jet device (15), such that the cavity is divided into a hot and a cold temperature region.
Silicon nanowire (SiNW) arrays for radial p-n junction solar cells offer potential advantages of light trapping effects and quick charge collection. Nevertheless, lower open circuit voltages (V (oc)) lead to lower energy conversion efficiencies. In such cases, the performance of the solar cells depends critically on the quality of the SiNW interfaces. In this study, SiNW core-shell solar cells have been fabricated by growing crystalline silicon (c-Si) nanowires via the metal-assisted chemical etching method and by depositing hydrogenated amorphous silicon (alpha-Si:H) via the plasma-enhanced chemical vapor deposition (PECVD) method. The influence of deposition parameters on the coverage and, consequently, the passivation and photovoltaic properties of alpha-Si:H layers on SiNW solar cells have been analyzed.
Because of the superior properties of copper, it has been of great interest as a conducting material to replace aluminum in device manufacturing. In this study, we investigated the influence of substrate temperature, film thickness, and rapid thermal annealing (RTA) on the deposition of Cu films of thickness less than 10 nm. Compared to thicker films, the electrical properties of nanometer-thick films were found to be very sensitive to the deposition temperature. Further, we determined the optimal deposition temperature to obtain low-resistivity nanometer-thick Cu films. The Cu films were deposited with island-type growth, and the interconnection between grains plays a major role in the resistivity of the films. We also determined the critical thickness at which Cu films exhibit continuous growth as 8 nm. After RTA, the film color darkened, electron scattering became weak, and the resistivity reduced more than 20% with annealing at 300-350 degrees C, because of the growth of Cu grains. The results of this study indicate that thermal ALD can be used in conjunction with RTA to produce low-resistivity Cu thin films, the thickness, uniformity, and conformality of which can be easily controlled. (C) 2015 Published by Elsevier B.V.
It is necessary to broaden the finite band gap of the graphene quantum dots (GQDs) and prepare deep ultraviolet emission GQDs with high luminescence efficiency. In this study, the deep ultraviolet emission ferric passivated GQDs (Fe-GQDs) are successfully prepared. Due to the strong negative inductive effect of Fe, the band gap of the Fe-GQDs was broadened, and the photoluminescence emission wavelength is 275 nm for an excitation at 224 nm with a very high fluorescent quantum yield (phi =3D 0.63). This is the shortest emission wavelength reported for solution-based inorganic and organic quantum dots. The high efficient ultraviolet emission, as well as the good stability and low in vitro cytotoxicity, may facilitate their applications to carbon-based light-emitting devices and lasers. (C) 2015 Elsevier B.V. All rights reserved.
Partial oxalate route is an efficient method to synthesize complex perovskite ferroelectric ceramics, in which the synthesized (1 - x) Pb(Mg1/3Nb2/3)O3-xPbTiO3 (PMN-PT) ceramics exhibit rather pure perovskite structure, densified microstructure morphology, and excellent dielectric and piezoelectric properties. The PMN-PT ceramics synthesized by the partial oxalate route exhibit rather symmetric strain-electric (S-E) field hysteresis loops, where the strain is large and far less than saturated at 2 kV/mm. The PMN-PT ceramics exhibit excellent pyroelectric properties, in which the values of the pyroelectric coefficient and the calculated pyroelectric figures of merit maintain almost stable over the frequency range of 100 Hz-2000 Hz, and vary differently depending on composition with the increase of temperature. Such investigations reveal that high-performance piezoelectric and pyroelectric devices can be prepared by the partial oxalate route in low production cost.
Wang, Run
Jiang, Nan
Su, Jian
Yin, Qu
Zhang, Yue
Liu, Zhongsheng
Lin, Haibao
Moura, Francisco A.
Yuan, Ningyi
Roth, Siegmar
Rome, Richard S.
Ovalle-Robles, Raquel
Inoue, Kanzan
Yin, Shougen
Fang, Shaoli
Wang, Weichao
Ding, Jianning
Shi, Linqi
Baughman, Ray H.
Liu, Zunfeng
Current research about resistive sensors is rarely focusing on improving the strain range and linearity of resistance-strain dependence. In this paper, a bi-sheath buckled structure is designed containing buckled carbon nanotube sheets and buckled rubber on rubber fiber. Strain decrease results in increasing buckle contact by the rubber interlayer and a large decrease in resistance. The resulting strain sensor can be reversibly stretched to 600%, undergoing a linear resistance increase as large as 102% for 0-200% strain and 160% for 200-600% strain. This strain sensor shows high linearity, fast response time, high resolution, excellent stability, and almost no hysteresis.
The zwitterion-coated polyamidoamine (ZC-PAMAM) dendrimer with ammonium and sulfonic acid groups has been synthesized and used as filler for the preparation of PBI-based composite membranes for direct methanol fuel cells. Polybenzimidazole (PBI)/ZC-PAMAM dendrimer composite membranes were prepared by casting a solution of PBI and ZC-PAMAM dendrimer, and then evaporating the solvent. The presence of ZC-PAMAM dendrimer was confirmed by FT-IR and energy-dispersive X-ray spectroscopy (EDS) mapping of sulfur and oxygen elements. The water uptake, swelling degree, proton conductivity, and methanol permeability of the membranes increased with the ZC-PAMAM dendrimer content. For the PBI/ZC-PAMAM-20 membrane with 20 wt% of ZC-PAMAM, it shows a proton conductivity of 1.83 x 10(-2) S/cm at 80 degrees C and a methanol permeability of 5.23 x 10(-8) cm(2) s(-1). Consequently, the PBI/ZC-PAMAM-20 demonstrates a maximum power density of 26.64 mW cm(-2) in a single cell test, which was about 2-fold higher than Nafion-117 membrane under the same conditions. Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.
Wang, Run
Boleij, Marissa
Yin, Qu
Galjart, Niels
Lin, Bencai
Yuan, Ningyi
Zhou, Xiang
Tan, Ming
Ding, Jianning
Liu, Zunfeng
Abrahams, Jan Pieter
In this study, Single walled carbon nanotube (SWNT)-streptavidin complexes were used to capture and purify biotinylated proteins, including bio-GFP and bio-DBS using a pull-down method. The purification conditions were systematically studied, including surface blocking of SWNT using chicken egg albumin (CEA), the ratio of SWNT-streptavidin complexes to the cell lysate, as well as the centrifugation speed. Optimization of the protein purification using SWNT-streptavidin complexes shows the possibility of carbon nanotubes as a promising candidate for protein purification applications. The SWNT-streptavidin could be used as a scaffold to analyze protein structure directly by cryo-transmission electron microscopy, which provides better understanding in protein-protein interactions and biological processes.
Flexible perovskite solar cells are new technology-based products developed by the global solar industry and are promising candidates for realizing a flexible and lightweight energy supply system for wearable and portable electronic devices. A critical issue for flexible perovskite solar cells is to achieve high power conversion efficiency (PCE) while using low-temperature solution-based technology for the fabrication of a compact charge collection layer. Herein, we innovatively introduce niobium ethoxide as a precursor additive to TiO2 NCs, which allows realization of an Nb2O5-TiO2 electron transport layer (ETL). The presence of Nb2O5 remarkably enhances electron mobility and electrical conductivity of the ETLs. In addition, uniform perovskite films are prepared by an annealing-free solution-based method. The excellent performance of the cell is attributed to its smooth film surface and high electron mobility, and performance is verified by the effective suppressions of charge recombination and time-resolved photoluminescence. PCEs of 15.25% and 13.60% were obtained for rigid substrates (glass/fluorine-doped tin oxide) and an indium tin oxide/PET (poly(ethylene terephthalate)) flexible substrate by using a totally room-temperature solution-processing method, respectively.
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