全文获取类型
收费全文 | 266篇 |
免费 | 197篇 |
国内免费 | 140篇 |
专业分类
化学 | 304篇 |
晶体学 | 27篇 |
力学 | 2篇 |
综合类 | 2篇 |
物理学 | 268篇 |
出版年
2024年 | 7篇 |
2023年 | 22篇 |
2022年 | 55篇 |
2021年 | 39篇 |
2020年 | 40篇 |
2019年 | 23篇 |
2018年 | 28篇 |
2017年 | 32篇 |
2016年 | 33篇 |
2015年 | 25篇 |
2014年 | 46篇 |
2013年 | 65篇 |
2012年 | 31篇 |
2011年 | 33篇 |
2010年 | 24篇 |
2009年 | 14篇 |
2008年 | 12篇 |
2007年 | 20篇 |
2006年 | 8篇 |
2005年 | 4篇 |
2004年 | 9篇 |
2003年 | 4篇 |
2002年 | 3篇 |
2001年 | 3篇 |
2000年 | 2篇 |
1998年 | 6篇 |
1997年 | 2篇 |
1995年 | 2篇 |
1993年 | 1篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1985年 | 6篇 |
排序方式: 共有603条查询结果,搜索用时 15 毫秒
501.
Two-dimensional materials have attracted great attention because of their ultra-thin atomic layer thickness and high carrier mobility. In this work, we investigated the electronic transport of in-plane (IP) heterojunction based on Cu/Blue Phosphorus (BlueP), and the results suggest the metallization at the IP Cu/BlueP contact interface and a small Schottky barrier. Then, we investigated the performance of 5.1 nm IP BlueP Schottky barrier field-effect transistors (SBFET) with different dielectrics (SiO2, Al2O3, Y2O3, and La2O3) using quantum transport simulations. The results show that IP BlueP SBFETs with four dielectrics satisfy the off-state requirement of the International Technology Roadmap for Semiconductors (ITRS) for the high-performance (HP) device. However, the on-state current of only IP BlueP SBFET with La2O3 satisfies the requirements of ITRS. This will provide a reference for designing BlueP SBFETs. 相似文献
502.
Ming-Yang Li Hang Yin Ming-Yue Sui Fei Wang Yan-Hui Liu Guang-Yan Sun 《International journal of quantum chemistry》2019,119(15):e25938
The charge transfer (CT) mechanism at the donor/acceptor (D/A) interface plays an irreplaceable role in the photoelectric conversion of efficient bulk-heterojunction (BHJ) organic solar cells (OSCs), which affects the resulting competition between charge separation and charge recombination. Extensive CT studies have preferred monoadduct fullerene derivatives ( M60 , M70 ) due to their unique spherical geometry with fewer factors to consider. However, the effect of carbon cage size, substituent group properties and the number of CT properties have not been much discussed. Here, sulfur-containing bisadducts ( B60 , B70 ) were selected to explore whether they are also suitable for CT research like classical monoadducts. Using density functional theory and time-dependent density functional theory, interface stacking configuration, key parameters relevant to CT states, charge separation, and recombination rates were determined to confirm the characteristics of B60 and B70 as a good acceptor applied to interfacial research. This work points to the CT mechanism along the route of DA → D*A → D+A− through a theoretical analysis and also provides candidates for the theoretical interface photoelectric process in BHJ OSCs: bisadduct fullerene derivatives as good acceptor materials. 相似文献
503.
Comprehensive study of pyrido[3,4‐b]pyrazine‐based D–π–a copolymer for efficient polymer solar cells 下载免费PDF全文
Yun‐Siou Yang Sheng Hsiung Chang Pin‐Jiun Wu Yen‐Yi Chu Chun‐Guey Wu 《Journal of polymer science. Part A, Polymer chemistry》2016,54(12):1822-1833
Two D–π–A copolymers, based on the benzo[1,2‐b:4,5‐b′]‐dithiophene (BDT) as a donor unit and benzo‐quinoxaline (BQ) or pyrido‐quinoxaline (PQ) analog as an acceptor (PBDT‐TBQ and PBDT‐TPQ), were designed and synthesized as a p‐type material for bulk heterojunction (BHJ) photovoltaic cells. When compared with the PBDT‐TBQ polymer, PBDT‐TPQ exhibits stronger intramolecular charge transfer, showing a broad absorption coverage at the red region and narrower optical bandgap of 1.69 eV with a relatively low‐lying HOMO energy level at ?5.24 eV. The experimental data show that the exciton dissociation efficiency of PBDT‐TPQ:PC71BM blend is better than that in the PBDT‐TBQ:PC71BM blend, which can explain that the IPCE spectra of the PBDT‐TPQ‐based solar cell were higher than that of the PBDT‐TBQ‐based solar cell. The maximum efficiency of PBDT‐TPQ‐based device reaches 4.40% which is much higher than 2.45% of PBDT‐TBQ, indicating that PQ unit is a promising electron‐acceptor moiety for BHJ solar cells. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 1822–1833 相似文献
504.
半导体异质结光催化剂因其在太阳能利用和转化方面广阔的应用前景而备受关注。合理构建两种或两种以上半导体材料的异质结构,可以集成多种组分的优点,改善光生电荷分离,扩大对可见光的吸收范围,保持光催化剂的高氧化还原能力。近年来,由于g-C3N4具有合成简单、稳定性高、独特的光学和电学特性等诸多优点,g-C3N4基异质结构的构建成为研究热点。本文针对近年来g-C3N4基异质结改性的研究现状,依据g-C3N4与其他半导体电荷转移路径的不同综述了三种异质结结构(g-C3N4基Ⅱ型异质结、g-C3N4基Z型异质结和g-C3N4基S型异质结),以及其在环境修复和能源方面的应用。最后对g-C3N4基异质结光催化剂存在的问题进行总结和展望。 相似文献
505.
Searching for high-performance and cost-effective catalysts is of particular importance for the practical electrocatalysis applications. The heterojunctions with components in different dimensions show unique physical and chemical properties, which can offer large space for rational design of electrocatalysts. In this paper, we firstly reviewed recently related works, and then proposed a few perspectives on exploring heterojunction for electrocatalysis applications. 相似文献
506.
《Current Applied Physics》2014,14(3):340-344
We present an analytical model for bulk heterojunction organic solar cells incorporating the physics of recombination in the transport equations. Monomolecular recombination process is considered to be the dominant mechanism and treated explicitly. The proposed analytical model shows good agreement with the experimental data as well as with the numerical simulations. The improvements over the previous models are also presented to show the importance of considering the recombination process. The model can be used to find device characteristics such as current–voltage characteristic, efficiency etc. of bulk heterojunction organic solar cells avoiding the mathematical complexities of numerical models. 相似文献
507.
《化学:亚洲杂志》2017,12(16):2052-2056
The incorporation of fluorine atoms in organic semiconducting materials has attracted much attention recently due to its unique function to manipulate the molecular packing, film morphology and molecular energy levels. In this work, two perylenediimide (PDI) derivatives FPDI‐CDTph and FPDI‐CDTph2F were designed and synthesized to investigate the impact of fluorination on non‐fullerene acceptors. Both FPDI‐CDTph and FPDI‐CDTph2F exhibited strong and broad absorption profiles, suitable lowest unoccupied molecular orbital (LUMO) and highest occupied molecular orbital (HOMO) energy levels, and good electron transport ability. Compared with FPDI‐CDTph, the fluorinated acceptor (FPDI‐CDTph2F) afforded an optimal bulk heterojunction morphology with an interconnected and nanoscale phase separated structure that allowed more efficient exciton dissociation and balanced charge transport. Consequently, organic solar cells based on FPDI‐CDTph2F showed a much higher power conversion efficiency (PCE) of 6.03 % than that of FPDI‐CDTph based devices (4.10 %) without any post‐fabrication treatment. 相似文献
508.
Inorganic and organic semiconductor devices are generally viewed as distinct and separate technologies. Herein we report a hybrid inorganic-organic light-emitting device employing the use of an air stable polymer, Poly (9,9-dioctylfluorene-alt-benzothiadiazole) as a p-type layer to create a heterojunction, avoiding the use of p-type GaN, which is difficult to grow, being prone to the complex and expensive fabrication techniques that characterises it. I-V characteristics of the GaN-polymer heterojunction fabricated by us exhibits excellent rectification. The luminescence onset voltage is typically about 8-10 V. The device emits yellowish white electroluminescence with CIE coordinates (0.42, 0.44). 相似文献
509.
Rhodium‐catalyzed transfer hydrogenation with aminophosphines and analysis of electrical characteristics of rhodium(I) complex/n‐Si heterojunctions 下载免费PDF全文
Murat Aydemir Yusuf Selim Ocak Khadichakhan Rafikova Nurzhamal Kystaubayeva Cezmi Kayan Alexey Zazybin Fatih Ok Akın Baysal Hamdi Temel 《应用有机金属化学》2014,28(6):396-404
A series of novel neutral mononuclear rhodium(I) complexes of the P―NH ligands have been prepared starting from [Rh(cod)Cl]2 complex. Structural elucidation of the complexes was carried out by elemental analysis, IR and multinuclear NMR spectroscopic data. The complexes were applied to the transfer hydrogenation of acetophenone derivatives to 1‐phenylethanol derivatives in the presence of 2‐propanol as the hydrogen source. Catalytic studies showed that all complexes are also excellent catalyst precursors for transfer hydrogenation of aryl alkyl ketones in 0.1 m iso‐PrOH solution. In particular, [Rh(cod)(PPh2NH―C6H4―4‐CH(CH3)2)Cl] acts as an excellent catalyst, giving the corresponding alcohols in excellent conversion up to 99% (turnover frequency ≤ 588 h?1). Furthermore, rhodium(I) complexes have been used in the formation of organic–inorganic heterojunction by forming their thin films on n‐Si and evaporating Au on the films. It has been seen that the structures have rectifying properties. Their electrical properties have been analyzed with the help of current–voltage measurements. Finally, it has been shown that the complexes can be used in the fabrication of temperature and light sensors. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
510.