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Wang Y Tong SW Xu XF Ozyilmaz B Loh KP 《Advanced materials (Deerfield Beach, Fla.)》2011,23(13):1514-1518
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Jung Kyu Kim Sung Uk Chai Yoonjun Cho Lili Cai Sung June Kim Sangwook Park Jong Hyeok Park Xiaolin Zheng 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(42)
Mesoporous TiO2 nanoparticle (NP) films are broadly used as electrodes in photoelectrochemical cells, dye‐sensitized solar cells (DSSCs), and perovskite solar cells (PSCs). State‐of‐the‐art mesoporous TiO2 NP films for these solar cells are fabricated by annealing TiO2 paste‐coated fluorine‐doped tin oxide glass in a box furnace at 500 °C for ≈30 min. Here, the use of a nontraditional reactor, i.e., flame, is reported for the high throughput and ultrafast annealing of TiO2 paste (≈1 min). This flame‐annealing method, compared to conventional furnace annealing, exhibits three distinct benefits. First, flame removes polymeric binders in the initial TiO2 paste more completely because of its high temperature (≈1000 °C). Second, flame induces strong interconnections between TiO2 nanoparticles without affecting the underlying transparent conducting oxide substrate. Third, the flame‐induced carbothermic reduction on the TiO2 surface facilitates charge injection from the dye/perovskite to TiO2. Consequently, when the flame‐annealed mesoporous TiO2 film is used to fabricate DSSCs and PSCs, both exhibit enhanced charge transport and higher power conversion efficiencies than those fabricated using furnace‐annealed TiO2 films. Finally, when the ultrafast flame‐annealing method is combined with a fast dye‐coating method to fabricate DSSC devices, its total fabrication time is reduced from over 3 h to ≈10 min. 相似文献
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Hong Bin Yang Bin Liu Si Yun Khoo Lin Nan Zhu Chun Xian Guo Yong Qiang Dong Chang Ming Li 《Advanced Materials Interfaces》2014,1(3)
P‐type dye sensitized solar cells (p‐DSCs) deliver much lower overall efficiency than their inverse model, n‐DSCs. However, they have fundamental and practical significance, in particular, their tandem structured solar cells with both p‐ and n‐photoelectrodes could offer great potential to significantly improve the efficiency of existing solar cells. A facile and environmentally friendly method is developed to directly one‐step grow hollow NiO spherical structures on fluorine‐doped tin oxide (FTO) substrate, in which a Ni2+ and polymer complex spherical structure is self‐constructed through a controlled solvent evaporation process, followed by calcination‐converting to a unique NiO hollow sphere film. The prepared material is further used as a photocathode in p‐type dye sensitized solar cells, resulting in 41% increase of an open‐circuit voltage and 18% enhancement of power conversion efficiency than NiO nanoparticles photocathode. The improved performance can be ascribed to suppressed charge recombination at the photocathode/electrolyte interface. This template‐free approach could be universally used to fabricate other nanostructured hollow spheres for a wide range of energy conversion applications such as electrochemical capacitors, chemical sensors, and electrochromic devices. 相似文献
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Yong Cui Shaoqing Zhang Ningning Liang Jingyi Kong Chenyi Yang Huifeng Yao Lijiao Ma Jianhui Hou 《Advanced materials (Deerfield Beach, Fla.)》2018,30(34)
The solution‐processed layer‐by‐layer (LBL) method has potential to achieve high‐performance polymer solar cells (PSCs) due to its advantage of enriching donors near the anode and acceptors near the cathode. However, power conversion efficiencies (PCEs) of the LBL‐PSCs are still significantly lower than those of conventional one‐step‐processed PSCs (OS‐PSCs). A method to solve the critical problems in LBL‐PSCs is reported here. By employing a specific mixed solvent (o‐dichlorobenzene [o‐DCB]/tetrahydrofuran) to spin‐coat the small‐molecular acceptor IT‐4F onto a layer of the newly designed polymer donor (PBDB‐TFS1), appropriate interdiffusion between the PBDB‐TFS1 and the IT‐4F can critically be controlled, and then an ideal phase separation of the active layer and large donor/acceptor interface area can be realized with a certain amount of o‐DCB. The PSCs based on the LBL method exhibit PCEs as high as 13.0%, higher than that of the counterpart (11.8%) made by the conventional OS solution method. This preliminary work reveals that the LBL method is a promising approach to the promotion of the photovoltaic performance of polymer solar cells. 相似文献
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Ling‐Ling Wu Jia‐jun Wang Xia He Tao Zhang Hui Sun 《Packaging Technology and Science》2014,27(9):693-700
The ultra‐thin (polyethyleneimine/graphene oxide)n [(PEI/GO)n]multilayer films on poly(lactic acid) (PLA) were constructed via the layer‐by‐layer assembly. Here, the electrostatic interactions between PEI and GO were used to obtain the nanoscale composite membrane of (PEI/GO)n on the surface of PLA film. With the number of assembling layers increased, the oxygen permeability (PO2) of PLA film decreased substantially. As a 0.06 wt% GO solution was used with only four layers, the PO2 decreased from 53.8 to 0.377 × 10?4 cm3/m2/d/Pa, only 0.7% of the original PLA film. At the same time, the coated PLA film also presented a good transparency and better mechanical properties. It is a novel way to use GO on biodegradable packaging materials. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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Yan Ren Feng Nan Lu You Yang Zhou Yanyan Wang Junling Wang Xiaodong Su Mingrong Shen Liang Fang 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(16)
BiFeO3 (BFO)‐based ferroelectrics have been proved to be visible‐light‐driven photoelectrodes for O2 production. However, the hitherto reported photoelectrochemical performances remain inferior to meet the requirements for any applications. Besides, expensive noble metals (Ag, Au) are commonly required to achieve high photoelectric conversion efficiency. Here, the significant enhancements of photoelectrochemical performance is reported by fabricating a noble‐metal‐free reduced graphene oxide (RGO)/BFO composite film via a simple and cost‐effective solution process. The optimized RGO/BFO composite film exhibits a 600% improvement of the short‐circuit photocurrent density compared to that of the pristine BFO, and also outperforms the noble‐metal/BFO cells under the same reaction conditions. Furthermore, the incident photon‐to‐current efficiency of the optimized RGO/BFO sample shows threefold enhancement. This study delivers a facile and low‐cost approach to preparing 2D materials/ferroelectric heterostructures and offers a promising pathway to boost the performance of semiconducting ferroelectric photoelectrodes. 相似文献
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Bin Wang Benjamin V. Cunning Na Yeon Kim Fariborz Kargar Sun‐Young Park Zhancheng Li Shalik R. Joshi Li Peng Vijayakumar Modepalli Xianjue Chen Yongtao Shen Won Kyung Seong Youngwoo Kwon Jeongsu Jang Haofei Shi Chao Gao Gun‐Ho Kim Tae Joo Shin Kwanpyo Kim Ju‐Young Kim Alexander A. Balandin Zonghoon Lee Rodney S. Ruoff 《Advanced materials (Deerfield Beach, Fla.)》2019,31(29)
A macroscopic film (2.5 cm × 2.5 cm) made by layer‐by‐layer assembly of 100 single‐layer polycrystalline graphene films is reported. The graphene layers are transferred and stacked one by one using a wet process that leads to layer defects and interstitial contamination. Heat‐treatment of the sample up to 2800 °C results in the removal of interstitial contaminants and the healing of graphene layer defects. The resulting stacked graphene sample is a freestanding film with near‐perfect in‐plane crystallinity but a mixed stacking order through the thickness, which separates it from all existing carbon materials. Macroscale tensile tests yields maximum values of 62 GPa for the Young's modulus and 0.70 GPa for the fracture strength, significantly higher than has been reported for any other macroscale carbon films; microscale tensile tests yield maximum values of 290 GPa for the Young's modulus and 5.8 GPa for the fracture strength. The measured in‐plane thermal conductivity is exceptionally high, 2292 ± 159 W m?1 K?1 while in‐plane electrical conductivity is 2.2 × 105 S m?1. The high performance of these films is attributed to the combination of the high in‐plane crystalline order and unique stacking configuration through the thickness. 相似文献
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Adila Rani Dhinesh Babu Velusamy Richard Hahnkee Kim Kyungwha Chung Filipe Marques Mota Cheolmin Park Dong Ha Kim 《Small (Weinheim an der Bergstrasse, Germany)》2016,12(44):6167-6174
2D nanomaterials have been actively utilized in non‐volatile resistive switching random access memory (ReRAM) devices due to their high flexibility, 3D‐stacking capability, simple structure, transparency, easy fabrication, and low cost. Herein, it demonstrates re‐writable, bistable, transparent, and flexible solution‐processed crossbar ReRAM devices utilizing graphene oxide (GO) based multilayers as active dielectric layers. The devices employ single‐ or multi‐component‐based multilayers composed of positively charged GO (N‐GO(+) or NS‐GO(+)) with/without negatively charged GO(‐) using layer‐by‐layer assembly method, sandwiched between Al bottom and Au top electrodes. The device based on the multi‐component active layer Au/[N‐GO(+)/GO(‐)]n/Al/PES shows higher ON/OFF ratio of ≈105 with switching voltage of ?1.9 V and higher retention stability (≈104 s), whereas the device based on single component (Au/[N‐GO(+)]n/Al/PES) shows ≈103 ON/OFF ratio at ±3.5 V switching voltage. The superior ReRAM properties of the multi‐component‐based device are attributed to a higher coating surface roughness. The Au/[N‐GO(+)/GO(–)]n/Al/PES device prepared from lower GO concentration (0.01%) exhibits higher ON/OFF ratio (≈109) at switching voltage of ±2.0 V. However, better stability is achieved by increasing the concentration from 0.01% to 0.05% of all GO‐based solutions. It is found that the devices containing MnO2 in the dielectric layer do not improve the ReRAM performance. 相似文献
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Xiaoxi Zhou Bin Luo Ke Kang Yujia Zhang Peipei Jiang Fang Lan Qiangying Yi Yao Wu 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(17)
Downstream studies of circulating tumor cells (CTCs), which may provide indicative evaluation information for therapeutic efficacy, cancer metastases, and cancer prognosis, are seriously hindered by the poor purity of enriched CTCs as large amounts of interfering leukocytes still nonspecifically bind to the isolation platform. In this work, biomimetic immunomagnetic nanoparticles (BIMNs) with the following features are designed: i) the leukocyte membrane camouflage, which could greatly reduce homologous leukocyte interaction and actualize high‐purity CTCs isolation, is easily extracted by graphene nanosheets; ii) facile antibody conjugation can be achieved through the “insertion” of biotinylated lipid molecules into leukocyte‐membrane‐coated nanoparticles and streptavidin conjunction; iii) layer‐by‐layer assembly techniques could integrate high‐magnetization Fe3O4 nanoparticles and graphene nanosheets efficiently. Consequently, the resulting BIMNs achieve a capture efficiency above 85.0% and CTCs purity higher than 94.4% from 1 mL blood with 20–200 CTCs after 2 min incubation. Besides, 98.0% of the isolated CTCs remain viable and can be directly cultured in vitro. Moreover, application of the BIMNs to cancer patients' peripheral blood shows good reproducibility (mean relative standard deviation 8.7 ± 5.6%). All results above suggest that the novel biomimetic nanoplatform may serve as a promising tool for CTCs enrichment and detection from clinical samples. 相似文献
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The electronic structures and catalytic efficacies of molybdenum disulfide (MoS2)‐based catalysts are sensitive to embedding environment. In order to develop a finely tunable strategy, a “layer‐by‐layer and Nafion capping” strategy for the scalable preparation of interfacial (MoS2)‐based catalytic structures is developed. The study shows that the assembly partner influences the electronic structures of the Zn&N co‐doped (MoS2) (Zn‐N‐(MoS2)) catalysts. Poly(allylamine hydrochloride) (PAH) decreases the catalytic efficacy, whereas when PAH‐rGO (rGO [reduced graphene oxide]) is the assembly partner, effective interfacial catalysts are prepared. The superior catalytic efficacy of (PAH‐rGO/Zn‐N‐(MoS2))n can be attributed to the fact that rGO effectively activates the basal plane S2− as the active sites. The catalytic efficacy of the multilayers at 16 assembly cycles due to a balance between the number of active sites and low resistance. After capping with Nafion layer, the interfacial catalysts exhibit high stability. Compared with the widely used drop‐casting methods, the layer‐by‐layer strategy possesses unique benefits, including fine‐tune the structures, free choice of the partner, and planar homogeneity. It is expected that this layer‐by‐layer catalyst immobilization strategy will benefit fundamental understandings regarding the finely controlled scalable interfacial immobilization of catalysts with superior efficacy, and assist in promoting the practical utilization of various catalysts. 相似文献
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