Recently, lead halide perovskite (PVSK) polycrystalline films have drawn much attention as photoactive material and scored tremendous achievements in solar cells, photodetectors, light‐emitting diodes, and lasers owing to their engrossing optoelectronic properties and facile solution‐processed fabrication. However, large amounts of grain boundaries unfavorably induce ion migration, surface defect, and poor stability, impeding PVSK polycrystalline film‐based optoelectronic devices from practical application. In comparison with the polycrystalline counterparts, PVSK single crystals (SCs) with lower trap density serve as a better platform for not only fundamental research but also device applications. In light of this, the idea of using PVSK single crystals (SCs) to construct the optoelectronic devices is then proposed. Since then, a series of synthesis methods of PVSK SCs have emerged. In this review, recent progress of synthesis method of PVSK SCs is tried to be summarized and their advantages and limitations are analyzed. And then, the optoelectronic properties including carrier dynamic, defects, ion migration, and instability issues in these 3D and 2D PVSK SCs are overviewed and accordingly the proper device configurations of corresponding solar cells, photodetectors, X‐ray, γ‐ray detectors, etc., are proposed. It is believed that this review can provide the guidance for the further development of PVSK SCs and their applications.
Theoretical description of oscillations of electron liquid in large metallic nanospheres (with radius of few tens nm) is formulated within random-phase-approximation semiclassical scheme. Spectrum of plasmons is determined including both surface and volume type excitations. It is demonstrated that only surface plasmons of dipole type can be excited by homogeneous dynamical electric field. The Lorentz friction due to irradiation of electro-magnetic wave by plasmon oscillations is analyzed with respect to the sphere dimension. The resulting shift of resonance frequency turns out to be strongly sensitive to the sphere radius. The form of e-m response of the system of metallic nanospheres embedded in the dielectric medium is found. The theoretical predictions are verified by a measurement of extinction of light due to plasmon excitations in nanosphere colloidal water solutions, for Au and Ag metallic components with radius from 10 to 75 nm. Theoretical predictions and experiments clearly agree in the positions of surface plasmon resonances and in an emergence of the first volume plasmon resonance in the e-m response of the system for limiting big nanosphere radii, when dipole approximation is not exact.
The Volmer-Weber mode for growing polycrystalline films, which comprises island, network, and channel stages before the films become continuous, is well known for its complex stress behavior with compressive and tensile stress alternating in the initial three growth stages. Recently, two new mechanisms for the compressive stress have been proposed [Phys. Rev. Lett. 88, 156103 (2002); 89, 126103 (2002)], which account for the reversibility of stress generation and relaxation. We show that the two mechanisms play only minor roles for the development of compressive stress, which is confirmed to be due to capillarity effects in the precoalescence stage.
scattering so as to improve the performance or reduce the EM pollution. [1][2][3][4][5] With the extensive investigation in the past decades, various types of MAs have been developed and widely applied. Among them, magnetic MAs typically represented by composites containing ferrites or magnetic metal particles manifest much broader absorption bandwidth than nonmagnetic absorbers at the same thickness because of their high magnetic permeability. [6][7][8] However, they are reaching the ceiling of microwave absorption performance due to physical laws such as Snoek's limit, [9] as well as limited maneuverability of the material parameters. Moreover, they are all opaque due to the requirement of magnetic fillers with dark color. This makes them impossible to have the applications in window glass of stealth aircrafts and warships, [10] wireless local area network system, [11] radio frequency identification systems, [12] and electronic toll collection (ETC) system. [13] Recently, there have been increasing interests in metamaterials (MMs), which consist of sub-wavelength artificial unit cells. [14] With the proper design of the unit cells, the permittivity and permeability of MMs can be manipulated separately in a vast range beyond the conventional materials, bringing about some extraordinary properties, e.g., near-zero refractive index, [15] negative refraction, [16,17] and stimulating their applications in invisibility cloaks, [18,19] photon computer, [20] and super lens. [21] The design flexibility and abundant potential of the MMs also provide a chance to further improve the performance of MAs. [22][23][24][25] As a matter of fact, metamaterial absorbers (MMAs) have been demonstrated to show advantages such as near perfect absorption, [26] thin thickness, and light weight, [27] while the absorption bandwidth of MMAs has also been expanded significantly by developing a quantity of methods including the integration of multiple resonance units, [28,29] multilayered gradually varied structures, and more since their first demonstration. [30][31][32] Furthermore, for the absorption properties of MMAs depend highly on the structure and dimension of the unit cells rather than the optically obstructive microwave absorbing fillers as in conventional absorbers, the MMAs may also possess optical transparency. For example, the simple metamaterial consisting of indium tin oxide (ITO) square patches and a reflective backing spaced by a Optically transparent metamaterial microwave absorbers (MMAs) developed so far unexceptionally encounter an intrinsic contradiction between extending the absorption bandwidth and improving optical transparency, hindering their practical applications. This work, in its experiment and calculation, demonstrates an MMA with both broadband microwave absorption and excellent optical transparency by standing-up closed-ring resonators (CRRs) in an indium tin oxide backed Plexiglas board. The as-designed MMA shows a strong microwave absorption of 85% covering a wide frequency of 5.5-19.7 and 22.5-27.5 GHz u...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.