Anvar A. Zakhidov

Bio: Anvar A. Zakhidov is an academic researcher from University of Texas at Dallas. The author has contributed to research in topics: Perovskite (structure) & Carbon nanotube. The author has an hindex of 63, co-authored 417 publications receiving 27644 citations. Previous affiliations of Anvar A. Zakhidov include University of Texas System & Business International Corporation.

Perovskite Gain-Assisted Hyperbolic Metamaterials

Abstract: We experimentally demonstrate a type II hyperbolic metamaterials (HMMs) using the recently emerged perovskite gain material and Au. The hyperbolic dispersion of the fabricated device is investigated by measuring its polarization anisotropy.

Mixed Halide Perovskite Light Emitting Solar Cell

Abstract: Organic-inorganic halide perovskites recently have emerged as a promising material for highly effective light-emitting diodes (LEDs) and solar cells (SCs). Despite efficiencies of both perovskite SCs and LEDs are already among the best, the development of a perovskite dual functional device that is capable of working in these two regimes with high efficiencies is still challenging. Here we demonstrate that the dual functional device based on mixed halide perovskite CH3NH3PbBr2I can be switched from SC to LED with low threshold voltage Vth < 2 V by exposing to Sun at open circuit Voc or at small bias voltage of Vpol ~ 1 - 2 V. Such photo-poling creates in-situ p-i-n junction via methylammonium (CH3NH3+, MA+) and I-/Br- ions migration to interfaces, lowering charge injection barriers, and self-balancing injection currents in perovskite LED. We show that before the photo-poling, the electroluminescence (EL) is highly unstable in LED regime, whereas after the photo-poling, stabilized EL exhibits unusual dynamics, increasing with time and poling cycle number, while Vth and injection current decrease with cycling runs. Additionally, photo-induced and current-induced halide segregation accumulates with cycling, that is found beneficial for LED, increasing its efficiency and brightness, but reversibly degrading photovoltaic (PV) performance, which can be easily recovered.

Production and application of ribbon and sheet of nanofiber and twisted yarn and non-twisted yarn of nanofiber

Abstract: PROBLEM TO BE SOLVED: To provide a yarn, ribbon and sheet of nanofibers; to provide a method for producing the yarn, ribbon and sheet; and to provide applications of the yarn, ribbon and sheet.SOLUTION: In some embodiments, a yarn, ribbon and sheet of nanotubes include carbon nanotubes. Specifically, such carbon nanotubes of the present invention provide the following unique properties and property combinations, for example: extreme toughness; resistance to failure at knots; high levels of electrical and thermal conductivities; high absorption of energy that occurs reversibly; up to 13% of strain-to-failure as compared with a few percent in other fibers with similar toughness; very high resistance to creep; retention of strength even when heated in air at 450°C for one hour; and very high radiation resistance and UV resistance even when irradiated in air.

Anomalous behavior of electron spin resonance in KxC60 film prepared by electrochemical method

Abstract: Anomalous temperature dependence of the relative intensity ratio of three electron spin resonance (ESR) lines was observed in KxC60 films prepared by electrochemical doping in a solid electrolyte. From the ESR saturation curves of those lines measured at various temperatures, their spin-lattice relaxation times (T1) were estimated. Novel changes in the intensity among those lines with increasing microwave power can be explained by taking the difference in T1 of those lines into consideration. Under a relatively high doping condition the lowest T1 of 3.5×10-5 s was evaluated at 7.6 K.

Electrodeposition of Three-Dimensionally Periodic Metal Meshes and Spheres

Abstract: Electrochemical methods have been used to produce three-dimensionally periodic metal meshes and spheres. Nickel is initially deposited into porous opal sheets. The opals themselves consist of close-packed silica spheres, which serve as a template for the growth of the nickel arrays within the void space between SiO2 spheres. Dissolution of the SiO2 spheres results in open, three-dimensionally periodic nickel mesh structures. The metal meshes can then be oxidized in air to produce nonconducting NiO meshes. This results in an inverse template that can be used for the growth of three-dimensionally periodic metal sphere arrays. Details on the preparation and characterization of these materials are presented.

Electric Field Effect in Atomically Thin Carbon Films

Abstract: We describe monocrystalline graphitic films, which are a few atoms thick but are nonetheless stable under ambient conditions, metallic, and of remarkably high quality. The films are found to be a two-dimensional semimetal with a tiny overlap between valence and conductance bands, and they exhibit a strong ambipolar electric field effect such that electrons and holes in concentrations up to 10 13 per square centimeter and with room-temperature mobilities of ∼10,000 square centimeters per volt-second can be induced by applying gate voltage.

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

Carbon Nanotubes--the Route Toward Applications

Abstract: Many potential applications have been proposed for carbon nanotubes, including conductive and high-strength composites; energy storage and energy conversion devices; sensors; field emission displays and radiation sources; hydrogen storage media; and nanometer-sized semiconductor devices, probes, and interconnects. Some of these applications are now realized in products. Others are demonstrated in early to advanced devices, and one, hydrogen storage, is clouded by controversy. Nanotube cost, polydispersity in nanotube type, and limitations in processing and assembly methods are important barriers for some applications of single-walled nanotubes.