首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   211篇
  免费   69篇
  国内免费   9篇
化学   218篇
晶体学   1篇
数学   1篇
物理学   69篇
  2023年   2篇
  2022年   14篇
  2021年   16篇
  2020年   16篇
  2019年   23篇
  2018年   12篇
  2017年   20篇
  2016年   28篇
  2015年   16篇
  2014年   38篇
  2013年   29篇
  2012年   21篇
  2011年   25篇
  2010年   11篇
  2009年   3篇
  2008年   3篇
  2007年   2篇
  2006年   4篇
  2005年   2篇
  2003年   2篇
  2001年   2篇
排序方式: 共有289条查询结果,搜索用时 15 毫秒
51.
This article outlines state-of-the-art energy technologies, including production and storage, available to us through semiconductor nanomaterials. The nanostructure growth processes have been illustrated in detail, with emphasis on the latest developments in hierarchical and radial-composition modulated nanostructures. On the energy efficiency and generation part, light-emitting diodes, photovoltaics, photoelectrochemistry, thermoelectric, and fuel cells have been discussed. In the energy storage part, supercapacitors and lithium batteries have been discussed.  相似文献   
52.
In this study, we explored the ability of a preheated solvent (methanol) to induce characteristic changes at the organic active layer/metal interface, thereby improving the performance of fabricated organic photovoltaic (OPV) cells composed of poly(3-hexylthiopene) (P3HT) and a [6,6]-phenyl-C71-butyric acid methyl ester (PCBM) photoactive blend. Our results demonstrate that exposure to methanol (at room temperature, or preheated at 45 °C or 65 °C) improves the performance of the fabricated OPV cells. After preheated methanol exposure, the P3HT:PCBM thin films were tested for crystallinity, morphology, mobility, and photovoltaic characteristics. Our results revealed that use of the preheated solvent on the organic active layer significantly influences the micro/nano scale morphology and phase segregation of the P3HT:PCBM thin films, as well as the charge carrier mobility. It is hypothesized that the side chain ordering of P3HT and redistribution of PCBM could be results of the modified active layer. Consequently, OPV cells modified with the methanol preheated at 65 °C exhibited a power conversion efficiency (PCE) of 3.36%, with open-circuit voltage of 0.59 V, short-circuit current density of 13.83 mA/cm2, and fill-factor of 0.41. In contrast, the unmodified P3HT:PCBM thin film (without methanol exposure) showed a PCE of only 2.13%.  相似文献   
53.
JV characteristics and efficiency as a function of active region thickness of the p-i-n intermediate band solar cells have been calculated. We compared the maximum efficiency point of three different cells made of well-known materials. Each cell includes a different size of quantum dot in the i-region that causes different intermediate band position. Numerical optimizations have been done by adjusting parameters such as the combination of band gap, mismatch as well as the specific structure of the cell. In addition, it is illustrated that the maximum efficiency point increases with increasing the incident light concentration in the radiative limit. This article considered that using light concentrators can be useful to enhance the efficiency of the solar cell with respect to manufacturing and cost improvements.  相似文献   
54.
Four new solution-processible small-molecular platinum(II)-bis(aryleneethynylene) complexes consisting of benzothiadiazole as the electron acceptor and triphenylamine and/or thiophene as the electron donor were conveniently synthesized and characterized by physicochemical and computational methods, and utilized as the electron-donor materials in the fabrication of solution-processed bulk heterojunction (BHJ) solar cells. The effect of different electron-donor groups in these small molecules on the optoelectronic and photovoltaic properties was also examined. The optical and time-dependent density functional theory studies showed that the incorporation of stronger electron-donor groups significantly enhanced the solar-absorption abilities of the complexes. These molecular complexes can serve as good electron donors for fabricating BHJ devices by blending them with the [6,6]-phenyl-C(71)-butyric acid methyl ester (PC(70)BM) as the electron acceptor. The best power conversion efficiency of 2.37% was achieved with the open-circuit voltage of 0.83 V, short-circuit current density of 7.10 mA cm(-2) and fill factor of 0.40 under illumination of an AM 1.5 solar-cell simulator. The spin-coated thin films showed p-channel field-effect charge transport with hole mobilities of up to 2.4×10(-4) cm(2) V(-1) s(-1) for these molecules. The present work illuminates the potential of well-defined organometallic complexes in developing light-harvesting small molecules for efficient power generation in organic photovoltaics implementation.  相似文献   
55.
Low concentration photovoltaic (LCPV) systems have the potential to reduce the cost per kWh of electricity compared to conventional flat-plate photovoltaics (PV) by up to 50%. The cost-savings are realised by replacing expensive PV cells with relatively cheaper optical components to concentrate incident solar irradiance onto a receiver and by tracking the sun along either 1 axis or 2 axes. A LCPV module consists of three interrelated subsystems, viz., the optical, electrical and the thermal subsystems, which must be considered for optimal module design and performance. Successful integration of these subsystems requires the balancing of cost, performance and reliability. In this study LCPV experimental prototype modules were designed, built and evaluated with respect to optimisation of the three subsystems and overall performance. This paper reports on the optical and electrical evaluation of a prototype LCPV module.  相似文献   
56.
Many advances in organic photovoltaic efficiency are not yet fully understood and new insight into structure‐property relationships is required to push this technology into broad commercial use. The aim of this article is not to comprehensively review recent work, but to provide commentary on recent successes and forecast where researchers should look to enhance the efficiency of photovoltaics. By lowering the LUMO level, utilizing electron‐withdrawing substituents advantageously, and employing appropriate side chains on donor polymers, researchers can elucidate further aspects of polymer‐PCBM interactions while ultimately developing materials that will push past 10% efficiency.  相似文献   
57.
The quantum‐chemical investigations by ab initio method (restricted Hartree–Fock/6‐31G**) have been performed for a series of unsubstituted, monosubstituted, and disubstituted neutral polyenes and their double charged cations. The waves of charge alternation (characterized by the difference in the electron densities at the nearest carbon atoms or Δq function) and bond length alternation (characterized by the lengths difference of the nearest carbon–carbon bonds or Δl function) are reported. Comparisons are made with the corresponding monocationic polymethine molecules. We found that ionization by two electrons results in formation of two solitonic waves of charge alternation, rather than superposition of two overlapping solitonic waves into one. These waves behave similar to two independent elastic particles, which do not penetrate into each other despite the special confinement by the length of chromophore π‐system. In monosubstituted polyene dication, Δq and Δl functions contain two waves each; however, only one wave is mobile and sensitive to a change of the chemical nature of the terminal group, whereas the second wave remains practically unchanged. The introduction of one oxymethyl or phenyl terminal groups leads to a relatively small shift of the mobile wave from the center to a direction of the terminal group. The effect of the amino or tropilium terminal groups is much more pronounced and leads to a shift of the mobile wave to the end of the molecule. In disubstituted polyene dication, both solitonic waves become mobile and shift symmetrically to both ends. The general principles of the charge localization described in this study may be used in molecular design and fine‐tuning of the charge transport properties in plastic photovoltaics and other organic semiconducting materials. © 2012 Wiley Periodicals, Inc.  相似文献   
58.
We report a novel strategy for the front passivation of solar cells via aluminum-doped zinc oxide (AZO) films in the case of CIGS solar cells, leading to the highest efficiency of 15.07% without alkali metal post treatment and anti−reflective layer. The good passivation of CIGS solar cells via AZO films is attributed to the field passivation simulated by the SCAPS−1D software. The AZO films also exhibit high optical transparency both in visible and near infrared wavelength region, high conductivity, and cost−effective fabrication advantage. Importantly, the AZO films are deposited at room temperature via radio−frequency magnetron sputtering, showing that the AZO films are also applicable to other solar cells such as perovskite solar cells. Our work is of significance for advancing the development of CIGS−based photovoltaics devices by the well front passivation of AZO. The wide application of AZO in other solar cells such as perovskite solar cells and related tandem solar cells may also accelerate the development of these solar cells because of potential passivation of AZO, low deposition temperature, and high optical transparency of AZO.  相似文献   
59.
Abstract

This work reports the first investigation on the physical vapor deposition of thin films of tin sulfide doped lead sulfide (SnS:PbS). In-situ synthesis route using diethyldithiocarbamate (DTC) ligand was adopted for SnS-DTC, PbS-DTC and SnS:PbS-DTC complex formation. PbS-DTC and SnS:PbS-DTC expressed an average crystallite size of 30.98 and 29.74?nm, respectively shown by X-ray diffraction (XRD) analysis. A face centered cubic geometry was revealed from XRD. Ultraviolet visible spectrophotometry expressed a direct and indirect band gap of 3.4 and 3.2?eV, respectively for SnS:PbS-DTC. A smooth morphology with presence of larger agglomerated particles was disclosed by scanning electron microscopy for SnS:PbS-DTC thin films with 615?nm thickness. SnS:PbS-DTC thin films expressed remarkable electrochemical behavior explored via cyclic voltammetry, linear sweep voltammetry and chronoamperometry showing an improvement in the photo-current response upon potential bias increment. The results of the current research indicated the potential of SnS:PbS-DTC thin films for utilization in different types of photovoltaic devices.  相似文献   
60.
Mechanochemical synthesis of CsPbI3, as a model system for ABX3 halides, was studied. Water was shown to strongly promote the kinetics of formation of CsPbI3 from the CsI+PbI2 mixture through increased mobility of the constituting ionic species. Since many binary and ternary halides are hygroscopic, it was concluded that the presence of small, uncontrollable and unintentional additions of water should often occur in both precursor mixtures and synthesized complex halides boosting the kinetics of formation of many, if not all, ternary organic–inorganic hybrid halides such as, for example, MAPbX3 (X=Cl, Br, I). In addition, trace amounts of water should influence the transport characteristics of complex halides. Thus, the presence of water explains, at least partially, the huge scatter in both the reported mechanochemical reaction times necessary for obtaining single-phase APbX3 perovskite halides and the activation energies of ionic diffusion in APbX3.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号