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排序方式: 共有3425条查询结果,搜索用时 15 毫秒
1.
《Ceramics International》2022,48(12):16730-16736
Recently, all-inorganic cesium lead-halide perovskites have shown their promise for light emission applications, due to the excellent optical performance. Herein, we report that the initially nonphosphorescent undoped lead-halide Cs4PbBr6 single crystals (SCs) exhibit an ultralong phosphorescence emission under X-ray excitation at low temperatures. It is shown that the dramatic change has been taken place in radioluminescence spectra and the broad-band emission gradually appeared with the decrease of temperature. Below 210 K, the radioluminescence spectra can be deconvoluted into one narrow peak located at 530 nm and two broad peaks centered at 595 nm and 672 nm respectively. Subsequently, the time-dependent radioluminescence spectra in undoped lead-halide Cs4PbBr6 SCs were investigated. The ultralong phosphorescence emission can persist over 120 min at 70 K. We consider that ultralong phosphorescence originates from defect-related emission. To the best of our knowledge, our finding is the first time that undoped Cs4PbBr6 SCs exhibit the phosphorescence emission, which will offer a paradigm to motivate revolutionary applications on perovskite. 相似文献
2.
《Ceramics International》2020,46(4):4148-4153
The ferroelectric photovoltaic (FPV) effect obtained in inorganic perovskite ferroelectric materials has received much attention because of its large potential in preparing FPV devices with superior stability, high open-circuit voltage (Voc) and large short-circuit current density (Jsc). In order to obtain suitable thickness for the ferroelectric thin film as light absorption layer, in which, the sunlight can be fully absorbed and the photo-generated electrons and holes are recombined as few as possible, we prepare Pb0.93La0.07(Zr0.6Ti0.4)0.9825O3 (PLZT) ferroelectric thin films with different layer numbers by the sol-gel method and based on these thin films, obtain FPV devices with FTO/PLZT/Au structure. By measuring photovoltaic properties, it is found that the device with 4 layer-PLZT thin film (~300 nm thickness) exhibits the largest Voc and Jsc and the photovoltaic effect obviously depends on the value and direction of the poling electric field. When the device is applied a negative poling electric field, both the Voc and Jsc are significantly higher than those of the device applied the positive poling electric field, due to the depolarization field resulting from the remnant polarization in the same direction with the built-in electric field induced by the Schottky barrier, and the higher the negative poling electric field, the larger the Voc and Jsc. At a -333 kV/cm poling electric field, the FPV device exhibits the most superior photovoltaic properties with a Voc of as high as 0.73 V and Jsc of as large as 2.11 μA/cm2. This work opens a new way for developing ferroelectric photovoltaic devices with good properties. 相似文献
3.
《Journal of the European Ceramic Society》2020,40(5):2151-2162
Anorthite-based highly porous membranes were successfully produced using calcined oyster shell to enhance the pore network. The calcined oyster shells produce CaO responsible for the crystallisation of gehlenite and anorthite at relatively low temperature. While the crystallisation produced nano and meso size of intergranular pores, vitrification of feldspar is responsible for development of the capillary porosities. The increasing sintering temperature from 1200 °C to 1300 °C implies the increase in average pores radius from 1.2 μm to 14.3 μm due to the formation of spherical pores from vitrification. The combination of different class of porosities in the matrices results in the interconnection with improvement of the permeability of the porous network. Porosity, permeability and chemical stability were improved with 20 wt.% of calcined oyster shell addition allowing the possible development of high strength porous network which is promising for the membranes support and other applications including liquid separation as well as liquid filtration where high pressure is used. 相似文献
4.
A.V. GomonnaiI.M. Voynarovych A.M. SolomonYu.M. Azhniuk A.A. KikineshiV.P. Pinzenik M. Kis-VargaL. Daroczy V.V. Lopushansky 《Materials Research Bulletin》2003,38(13):1767-1772
Lattice structure and rod-like shaped SbSI nanocrystals obtained by ball milling with rod thickness down to 70 nm, as estimated from X-ray diffraction (XRD) and electron microscopy, is similar to that of the bulk crystals. The dependence of the grain size on the milling duration is discussed in view of the chain-like crystalline structure of SbSI. Possible factors, responsible for the observed Raman line broadening, are discussed, scattering by surface phonons being considered the predominant one. 相似文献
5.
本工艺是对原有工艺的改进,突破了原有布帮鞋不能采用无浆贴合的局限性,对原有工艺中的不足有了很大的改进,提高了生产效率,改善了鞋子外观质量,增加了鞋子的美观性。 相似文献
6.
HA型粘结剂性能评判的研究 总被引:2,自引:0,他引:2
冷固结球团直接还原工艺成功的关键因素之一是成型粘结剂的选用。粘结剂性能评判 ,传统的方法是通过考查球团矿的机械强度来说明粘结剂性能的优劣 ,步骤繁锁。经过试验研究 ,本文提出了用粘度大小来评判粘结剂性能的直接方法并从理论上进行了论证。对于 HA型复合粘结剂 ,在六速旋转粘度计上测量 ,50 g复合粘结剂的粘度若大于或等于 6.5× 1 0 -3 Pa·s,表示粘结剂性能较好 ,能满足铁精矿冷固球团直接还原工艺的要求 ;若小于或等于 3.0× 1 0 -3 Pa· s,则表示该粘结剂性能较差。 相似文献
7.
研究结果表明 :水胶比、胶凝材料用量、钢纤维掺量、矿渣代水泥量对钢纤维砼强度影响显著。当矿渣取代水泥 10 %时 ,钢纤维砼强度最高。经试验选择出一个具有良好和易性和较高强度 (118MPa)的钢纤维砼配合比 ,为掺磨细矿渣的中含量超短异形钢纤维砼的设计和施工提供了试验依据 相似文献
8.
A novel milk-like Cu-thiourea colloid has been synthesized. Nanocrystalline quaternary copper sulfide Cu2FeSnS4 was obtained through the Cu-thiourea colloidal precursor cooperative conversion route at low temperature. The samples were characterized by means of X-ray powder diffraction, transmission electron microscopy, scanning electron microscopy, inductively coupled plasma atomic emission spectroscopy, and X-ray energy dispersive spectroscopy techniques. The reaction details and features were described and discussed. 相似文献
9.
Thin layers of ceria were deposited on the surface of mica platelets in solution. The reaction of such particles with hydrogen sulfide yields a red colored special effect pigment. The ceria layer reacts with H2S to produce a variety of sulfide and oxysulfide phases. The reaction path discovered in situ by time and temperature resolved X-ray diffraction is CeO2→CeS2→C-Ce2S3→Ce10S14O. The reaction itself is extremely variable depending on gas flow, heating rates and decomposition atmospheres. Effects on the thin film are recorded by scanning electron microscopy (SEM) and revealed a destruction of the layer once red Ce10S14O was formed. The product layer then reveals the typical nonwetting behaviour of a liquid on a surface. 相似文献
10.
T.Z. Kosc K.L. Marshall Anka Trajkovska-Petkoska Erin Kimball S.D. Jacobs 《Displays》2004,25(5):171-176
Polymer cholesteric liquid crystal (PCLC) flake technology is being developed as an alternative display technology for flexible, reflective particle displays. The motion of PCLC flakes suspended in a host fluid can be controlled with an electric field, creating a way to electrically control the flakes' ability to brightly reflect light that is circularly polarized. The PCLC flake/host fluid dispersion has been successfully microencapsulated both in a polymer matrix and in gelatin micro-capsules. Microencapsulation will not only expand the applications scope of the technology, but also may aid in addressing some potential problem areas that are inherent to many forms of particle display technology. A second important development in PCLC flake technology involves the manufacture of shaped flakes based on soft lithography techniques. The size and shape of a flake impact its reorientation, and uniformly shaped flakes respond in a similar manner. The unique reflective properties of PCLC flakes also provide possible applications in areas such as optics and photonics, switchable ‘smart windows’ or conformal coatings, and information displays such as ‘electronic paper.’ 相似文献