共查询到20条相似文献，搜索用时 15 毫秒
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《Advanced Materials Interfaces》2018,5(9)
Perovskite solar cells (PSCs) are emerging among the photovoltaic (PV) technologies due to their high power conversion efficiency (PCE) in combination with potentially low cost manufacturing processing. In this contribution, the fabrication of efficient planar n‐i‐p PSCs by the modification of the electron transport layer (ETL) adopted as n‐type contact is demonstrated. Specifically, a fluorine‐based plasma treatment prior to perovskite deposition leads to surface fluorination of the TiO2 ETL. The presence of fluorine on the TiO2 surface drastically improves the adhesion between the ALD layer and the methylammonium lead iodide perovskite film, and leads to a more favourable energy band alignment, accompanied by a faster electron carrier extraction at the interface. As consequence of surface fluorination, we observe a significant reduction in the current density‐voltage curve hysteresis with respect to the ALD based reference sample, as well as a remarkable improvement in power conversion efficiency from 4% up to a stable 14.8%. 相似文献
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Chongyi Ling Yixin Ouyang Qiang Li Xiaowan Bai Xin Mao Aijun Du Jinlan Wang 《Small Methods》2019,3(9)
Electrocatalytic or photocatalytic N2 reduction holds great promise for green and sustainable NH3 production under ambient conditions, where an efficient catalyst plays a crucial role but remains a long‐standing challenge. Here, a high‐throughput screening of catalysts for N2 reduction among (nitrogen‐doped) graphene‐supported single atom catalysts is performed based on a general two‐step strategy. 10 promising candidates with excellent performance are extracted from 540 systems. Most strikingly, a single W atom embedded in graphene with three C atom coordination (W1C3) exhibits the best performance with an extremely low onset potential of 0.25 V. This study not only provides a series of promising catalysts for N2 fixation, but also paves a new way for the rational design of catalysts for N2 fixation under ambient conditions. 相似文献
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Lei Cheng Hui Yin Chao Cai Jiajie Fan Quanjun Xiang 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(28)
It is greatly intriguing yet remains challenging to construct single‐atomic photocatalysts with stable surface free energy, favorable for well‐defined atomic coordination and photocatalytic carrier mobility during the photoredox process. Herein, an unsaturated edge confinement strategy is defined by coordinating single‐atomic‐site Ni on the bottom‐up synthesized porous few‐layer g‐C3N4 (namely, Ni5‐CN) via a self‐limiting method. This Ni5‐CN system with a few isolated Ni clusters distributed on the edge of g‐C3N4 is beneficial to immobilize the nonedged single‐atomic‐site Ni species, thus achieving a high single‐atomic active site density. Remarkably, the Ni5‐CN system exhibits comparably high photocatalytic activity for CO2 reduction, giving the CO generation rate of 8.6 µmol g?1 h?1 under visible‐light illumination, which is 7.8 times that of pure porous few‐layer g‐C3N4 (namely, CN, 1.1 µmol g?1 h?1). X‐ray absorption spectrometric analysis unveils that the cationic coordination environment of single‐atomic‐site Ni center, which is formed by Ni‐N doping‐intercalation the first coordination shell, motivates the superiority in synergistic N–Ni–N connection and interfacial carrier transfer. The photocatalytic mechanistic prediction confirms that the introduced unsaturated Ni‐N coordination favorably binds with CO2, and enhances the rate‐determining step of intermediates for CO generation. 相似文献
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Ya‐Nan Sun Ming‐Li Zhang Li Zhao Zhu‐Yin Sui Zhen‐Yu Sun Bao‐Hang Han 《Advanced Materials Interfaces》2019,6(14)
Oxygen reduction reaction (ORR) is the critical reaction in metal–air batteries and fuel cells. This reaction suffers from sluggish kinetics and use of Pt‐based catalysts that are prohibitively expensive and in shortage of resource. Therefore, an alternative advanced metal‐free catalyst for ORR is highly desired. Herein, a N, P dual‐doped porous carbon (NPPC) with large surface area is obtained through the CO2 activation of a novel N, P‐doped aerogel (NPA). Ascribed to the CO2 activation of NPA, NPPC possesses a large Brunauer–Emmett–Teller specific surface area (2850 m2 g−1) and N, P dual doping. CO2 activation as an environmentally friendly method with no corrosion can not only produce abundant micropores and mesopores in NPPC, but also provide a positive influence for the transformation of N species from pyrrolic N to pyridinic and graphitic N, which can promote the ORR activities. Therefore, compared with carbonized NPA, NPPC exhibits a higher ORR activity, including a larger transfer electron number (3.95 at 0.2 V vs reversible hydrogen electrode). Additionally, NPPC possesses a much better long‐term stability compared with commercial 20 wt% Pt/C. This work gives an inspiration on the new strategy for preparing the future catalyst for ORR. 相似文献
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Hoon Ryu Martin Fuechsle Lloyd C. L. Hollenberg Michelle Y. Simmons Gerhard Klimeck 《Small (Weinheim an der Bergstrasse, Germany)》2015,11(3):374-381
A detailed theoretical study of the electronic and transport properties of a single atom transistor, where a single phosphorus atom is embedded within a single crystal transistor architecture, is presented. Using a recently reported deterministic single‐atom transistor as a reference, the electronic structure of the device is represented atomistically with a tight‐binding model, and the channel modulation is simulated self‐consistently with a Thomas‐Fermi method. The multi‐scale modeling approach used allows confirmation of the charging energy of the one‐electron donor charge state and explains how the electrostatic environments of the device electrodes affects the donor confinement potential and hence extent in gate voltage of the two‐electron charge state. Importantly, whilst devices are relatively insensitive to dopant ordering in the highly doped leads, a ～1% variation of the charging energy is observed when a dopant is moved just one lattice spacing within the device. The multi‐scale modeling method presented here lays a strong foundation for the understanding of single‐atom device structures: essential for both classical and quantum information processing. 相似文献
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使用等离子注入技术对SnO_2薄膜进行N离子注入改性,进行方块电阻、光学透过、表面形貌、Kelvin探针和X射线光电子能谱(XPS)表征,并将其作为缓冲层应用到CdTe太阳电池中。研究结果发现,对于30nm厚的SnO_2缓冲层,经过30s、10min不同时间N离子注入以后,其300~800nm波长范围透过率有所降低,而体电阻率则明显增加,特别是N离子注入10min的SnO_2缓冲层,表面出现很多凹孔,呈蜂窝状结构,且对后续沉积的CdS层表面形貌产生了明显影响。Kelvin探针表征结果显示,随着N离子注入时间的延长,SnO_2缓冲层功函数逐渐增加,最高达到约5.075eV,比本征SnO_2缓冲层的功函数高出0.15eV。XPS测试结果显示,N离子注入10min后,SnO_2缓冲层N1s结合能峰位向低结合能方向发生了明显移动,而O1s结合能峰位则向高结合能方向移动了,且表面区非晶格氧所占比例增大。对比电池结果,有N离子注入改性SnO_2缓冲层的电池与无缓冲层的电池相比,效率从10%左右增加到12%以上,最高达到12.47%,其中开路电压提高最为显著,从约750mV提高到790mV以上,提升了约5%,电池的整体均匀性也明显改善。 相似文献
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C. M. Yang A. T. Cho F. M. Pan T. G. Tsai K. J. Chao 《Advanced materials (Deerfield Beach, Fla.)》2001,13(14):1099-1102
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《Advanced Materials Technologies》2017,2(8)
WO2 nanowires have great potential as cold cathode materials because they exhibit excellent field‐emission properties in terms of their low work function and high conductivity. Considering the requirements of the practical applications in large‐area cold‐cathode devices, such as X‐ray source and panel display, these nanostructures are desired to be fabricated on glass substrate and integrated into devices. It is best known that the studies on WO2 nanowire cold cathode arrays grown on glass‐substrate are absent so far, which remains a challenge for the researchers. In the current study, procedures for fabrication of WO2 nanowire cold cathode arrays, which consist of 22000 separated patterns on 1.2 in. glass wafer are developed. It is found that the turn‐on and threshold field of the nanowire arrays are, respectively, 6.6 and 9.3 V µm−1. In addition, the performance of the cold cathode arrays is strongly affected by the distribution of the nanowire density as well as the thickness of Al electrode. By modifying the fabrication techniques, over 82% patterns can contribute to the emission, whereby a maximum current density can reach 1.89 mA cm−2. Such a value can fulfill the basic requirement of the large‐area cold cathode devices. The research can pave the way for fabrication of high‐performance cold cathode devices using glass‐substrates. 相似文献
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Zhiheng Wu Yongshang Zhang Yonglong Shen Wei Zhang Guosheng Shao 《Advanced Materials Interfaces》2020,7(18)
Vertically standing graphene (VSG) films have demonstrated various appealing functionalities on the basis of excellent electrical/thermal conductivity and electrochemical/catalytic properties, owing to their unique morphology, preferable orientation of the basal planes, and adequate defects as effective catalytic sites. Most fabrication processes for VSG suffer from the disadvantage of high processing temperature, difficulty in structural control, or poor scalability, which limits their many potential applications. Herein, a scalable high‐flux plasma‐enhanced chemical vapor deposition system is designed, with streamlined magnetic field to enable high and uniform ion density over a spatially extended plasma flux, which facilitates large‐area deposition of structurally tuned VSG independent of substrate materials without additional heating, for the first time. The orientation, density, and the degree of order for the as‐fabricated VSG can be tailored through adjusting the plasma environment, which in turn affects crystallization mechanisms. Such low‐temperature synthesized VSG films are demonstrated as high‐performance anode in sodium ion batteries, achieving a high capacity retention of 86% after 2000 cycles at a current density of 1 A g−1. It is expected that the current VSG films would have great potential for electrochemical applications that request catalytic sites together with favorable conductivity for ions and electrons. 相似文献
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简述了纳米Al2O3改性玻璃纤维增强环氧树脂基复合材料的制备,并对其常温、低温力学性能进行实验。结果表明,常温、低温下,复合材料的力学性能随着纳米Al2O3含量的增加都呈现先增强后减弱的趋势。低温处理使复合材料的力学性能得到提升,并且低温下Al2O3的引入对复合材料强度的改善效果比常温下明显,Al2O3含量为1%(质量分数)时,拉伸强度提高比例高达16.61%。其原因是低温下基体强度增大,另外基体热膨胀系数大,收缩明显,界面粘接强度增大,纳米Al2O3颗粒在界面处与树脂基体结合更深入,从而使纳米粒子阻碍微裂纹扩展的能力更强。 相似文献
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Changmiao Chen Yincai Yang Xuan Tang Renhua Qiu Shuangyin Wang Guozhong Cao Ming Zhang 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(10)
Developing low cost, long life, and high capacity rechargeable batteries is a critical factor towards developing next‐generation energy storage devices for practical applications. Therefore, a simple method to prepare graphene‐coated FeS2 embedded in carbon nanofibers is employed; the double protection from graphene coating and carbon fibers ensures high reversibility of FeS2 during sodiation/desodiation and improved conductivity, resulting in high rate capacity and long‐term life for Na+ (305.5 mAh g?1 at 3 A g?1 after 2450 cycles) and K+ (120 mAh g?1 at 1 A g?1 after 680 cycles) storage at room temperature. Benefitting from the enhanced conductivity and protection on graphene‐encapsulated FeS2 nanoparticles, the composites exhibit excellent electrochemical performance under low temperature (0 and ?20 °C), and temperature tolerance with stable capacity as sodium‐ion half‐cells. The Na‐ion full‐cells based on the above composites and Na3V2(PO4)3 can afford reversible capacity of 95 mAh g?1 at room temperature. Furthermore, the full‐cells deliver promising discharge capacity (50 mAh g?1 at 0 °C, 43 mAh g?1 at ?20 °C) and high energy density at low temperatures. Density functional theory calculations imply that graphene coating can effectively decrease the Na+ diffusion barrier between FeS2 and graphene heterointerface and promote the reversibility of Na+ storage in FeS2, resulting in advanced Na+ storage properties. 相似文献
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Guang Yang Hongwei Lei Hong Tao Xiaolu Zheng Junjie Ma Qin Liu Weijun Ke Zhiliang Chen Liangbin Xiong Pingli Qin Zhao Chen Minchao Qin Xinhui Lu Yanfa Yan Guojia Fang 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(2)
Despite the rapid increase of efficiency, perovskite solar cells (PSCs) still face some challenges, one of which is the current–voltage hysteresis. Herein, it is reported that yttrium‐doped tin dioxide (Y‐SnO2) electron selective layer (ESL) synthesized by an in situ hydrothermal growth process at 95 °C can significantly reduce the hysteresis and improve the performance of PSCs. Comparison studies reveal two main effects of Y doping of SnO2 ESLs: (1) it promotes the formation of well‐aligned and more homogeneous distribution of SnO2 nanosheet arrays (NSAs), which allows better perovskite infiltration, better contacts of perovskite with SnO2 nanosheets, and improves electron transfer from perovskite to ESL; (2) it enlarges the band gap and upshifts the band energy levels, resulting in better energy level alignment with perovskite and reduced charge recombination at NSA/perovskite interfaces. As a result, PSCs using Y‐SnO2 NSA ESLs exhibit much less hysteresis and better performance compared with the cells using pristine SnO2 NSA ESLs. The champion cell using Y‐SnO2 NSA ESL achieves a photovoltaic conversion efficiency of 17.29% (16.97%) when measured under reverse (forward) voltage scanning and a steady‐state efficiency of 16.25%. The results suggest that low‐temperature hydrothermal‐synthesized Y‐SnO2 NSA is a promising ESL for fabricating efficient and hysteresis‐less PSC. 相似文献
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采用氧化亚铜(Cu_2O)陶瓷靶,利用射频磁控溅射沉积法在氮气和氩气的混合气氛下制备了N掺杂Cu_2O(Cu_2O∶N)薄膜,并在N_2气氛下对薄膜进行了快速热退火处理,研究了N_2流量和退火温度对Cu_2O∶N薄膜的生长行为、物相结构、表面形貌及光电性能的影响。结果显示,在衬底温度300℃、N_2流量12sccm条件下生长的薄膜为纯相Cu_2O薄膜;在N_2气氛下对预沉积薄膜进行快速热退火处理不影响薄膜的物相结构,薄膜的结晶质量随退火温度(450℃)的升高而显著改善;快速热退火处理能改善薄膜的结晶质量和缺陷,降低光生载流子的散射,增强载流子的传输,预沉积Cu_2O∶N薄膜经400℃退火处理后展示出较好的电性能,薄膜的霍尔迁移率(μ)为27.8cm~2·V~(-1)·s~(-1)、电阻率(ρ)为2.47×10~3Ω·cm。研究表明低温溅射沉积和快速热退火处理能有效改善Cu_2O∶N薄膜的光电性能。 相似文献
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Fucong Lyu Shanshan Zeng Zhifang Sun Ning Qin Lujie Cao Zhenyu Wang Zhe Jia Shaofei Wu Fei‐Xiang Ma Minchan Li Wenxi Wang Yang Yang Li Jian Lu Zhouguang Lu 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(8)
Layered stacking and highly porous N, P co‐doped Mo2C/C nanosheets are prepared from a stable Mo‐enhanced hydrogel. The hydrogel is formed through the ultrafast cross‐linking of phosphomolybdic acid and chitosan. During the reduction of the composite hydrogel framework under inert gas protection, highly porous N and P co‐doped carbon nanosheets are produced with the in situ formation of ultrafine Mo2C nanoparticles highly distributed throughout the nanosheets which are entangled via a hierarchical lamellar infrastructure. This unique architecture of the N, P co‐doped Mo2C/C nanosheets tremendously promote the electrochemical activity and operate stability with high specific capacity and extremely stable cycling. In particular, this versatile synthetic strategy can also be extended to other polyoxometalate (such as phosphotungstic acid) to provide greater opportunities for the controlled fabrication of novel hierarchical nanostructures for next‐generation high performance energy storage applications. 相似文献
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Qingyue Wang Zhimin Li Miguel A. Baares Lu‐Tao Weng Qinfen Gu Jason Price Wei Han King Lun Yeung 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(42)
Mixed transition metal oxides (MTMOs) have enormous potential applications in energy and environment. Their use as catalysts for the treatment of environmental pollution requires further enhancement in activity and stability. This work presents a new synthesis approach that is both convenient and effective in preparing binary metal oxide catalysts (CeCuOx) with excellent activity by achieving molecular‐level mixing to promote aliovalent substitution. It also allows a single, pure MTMO to be prepared for enhanced stability under reaction by using a bimetallic metal–organic framework (MOF) as the catalyst precursor. This approach also enables the direct manipulation of the shape and form of the MTMO catalyst by controlling the crystallization and growth of the MOF precursor. A 2D CeCuOx catalyst is investigated for the oxidation reactions of methanol, acetone, toluene, and o‐xylene. The catalyst can catalyze the complete reactions of these molecules into CO2 at temperatures below 200 °C, representing a significant improvement in performance. Furthermore, the catalyst can tolerate high moisture content without deactivation. 相似文献
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Yangyang Feng Ting Zhang Jiahui Zhang Hao Fan Cheng He Jiangxuan Song 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(33)
Metallic phase (1T) MoS2 has been regarded as an appealing material for hydrogen evolution reaction. In this work, a novel interface‐induced strategy is reported to achieve stable and high‐percentage 1T MoS2 through highly active 1T‐MoS2/CoS2 hetero‐nanostructure. Herein, a large number of heterointerfaces can be obtained by interlinked 1T‐MoS2 and CoS2 nanosheets in situ grown from the molybdate cobalt oxide nanorod under moderate conditions. Owing to the strong interaction between MoS2 and CoS2, high‐percentage of metallic‐phase (1T) MoS2 of 76.6% can be achieved, leading to high electroconductivity and abundant active sites compared to 2H MoS2. Furthermore, the interlinked MoS2 and CoS2 nanosheets can effectively disperse the nanosheets so as to enlarge the exposed active surface area. The near zero free energy of hydrogen adsorption at the heterointerface can also be achieved, indicating the fast kinetics and excellent catalytic activity induced by heterojunction. Therefore, when applied in hydrogen evolution reaction (HER), 1T‐MoS2/CoS2 heterostructure delivers low overpotential of 71 and 26 mV at the current density of 10 mA cm?2 with low Tafel slops of 60 and 43 mV dec?1, respectively in alkaline and acidic conditions. 相似文献