Reversible Formation of Gold Halides in Single‐Crystal Hybrid‐Perovskite/Au Interface upon Biasing and Effect on Electronic Carrier Injection

Solar cells, light emitting diodes, and X‐ray detectors based on perovskite materials often incorporate gold electrodes, either in direct or indirect contact with the perovskite compound. Chemical interactions between active layers and contacts deteriorate the operation and induce degradation, being the identification of the chemical nature of such interfacial structures an open question. Chemical reactivity of gold in contact with the perovskite semiconductor leads to reversible formation of oxidized gold halide species and explains the generation of halide vacancies in the vicinity of the interface. Electrical biasing induces contact reaction and produces modifications of the current level by favoring the ability of perovskite/Au interfaces to inject electronic carriers. The current injection increment does not depend on the halogen source used, either extrinsically by iodine vapor sublimation of Au electrodes, or intrinsically by bias‐driven migration of bromide ions. In addition, the formation of a dipole‐like structure at the reacted electrode that lowers the potential barrier for electronic carriers is confirmed. These findings highlight adequate selection of the external contacts and suggest the need for a deeper understanding of contact reactivity as it dominates the operation characteristics, rather than being governed by the bulk transport properties of the charge carriers, either electronic or ionic

Unconventional methods in voynich manuscript analysis

This paper discusses the possible use of unconventional algorithms on analysis and categorization of the unknown text, including documents written in unknown languages. Scholars have identified about ten famous manuscripts, mostly encrypted or written in the unknown language. The most famous is the Voynich manuscript, an illustrated codex hand-written in an unknown language or writing system. Using carbon-dating methods, the researchers determined its age as the early 15th century (between 1404-1438). Many professional and amateur cryptographers have studied the Voynich manuscript, and none has deciphered its meaning as yet, including American and British code-breakers and cryptologists. While there exist many hypotheses about the meaning and structure of the document, they have yet to be confirmed empirically. In this paper, we discuss two different kinds of unconventional approaches for how to handle manuscripts with unidentified writing systems and determine whether its properties are characterized by a natural language, or is only historical fake text

Unconventional Methods in Voynich Manuscript Analysis

This paper discusses the possible use of unconventional algorithms on analysis and categorization of the unknown text, including documents written in unknown languages. Scholars have identied about ten famous manuscripts, mostly encrypted or written in the unknown language. The most famous is the Voynich manuscript, an illustrated codex hand-written in an unknown language or writing system. Using carbon-dating methods, the researchers determined its age as the early 15th century (between 1404-1438). Many professional and amateur cryptographers have studied the Voynich manuscript, and none has deciphered its meaning as yet, including American and British code-breakers and cryptologists. While there exist many hypotheses about the meaning and structure of the document, they have yet to be conrmed empirically. In this paper, we discuss two dierent kinds of unconventional approaches for how to handle manuscripts with unidentied writing systems and determine whether its properties are characterized by a natural language, or is only historical fake text

GRAPHENE- AND GRAPHITE OXIDE-REINFORCED MAGNESIUM OXYCHLORIDE CEMENT COMPOSITES FOR THE CONSTRUCTION USE

Graphene and graphite oxide reinforced magnesium oxychloride cement (MOC) pastes were researched. To produce MOC pastes, the light-burnt magnesium oxide was added and dispersed in the magnesium chloride solution. The graphene powder, graphite oxide powder, and their combination were incorporated in the solution. The total amount of the nano additives was 0.5% by the weight of the magnesium oxychloride binder. The morphology and microstructure of the hardened materials were studied using scanning electron microscopy (SEM). The phase composition of precipitated MOC-based products was investigated using X ray diffraction (XRD). The macrostructural parameters of the composites such as bulk density, specific density, and open porosity were evaluated. Mechanical strength and stiffness were analyzed by the measurement of flexural and compressive strength and dynamic elastic modulus. The electrical properties were examined by the use of impedance spectroscopy (IS). From the experimental results the model of the transport of electric charge in researched materials dispersion was estimated. The use of graphene- and graphite oxide-reinforcement of MOC matrix gave highly dense materials of low porosity, high mechanical resistance, whereas the used nano-additives enabled the produce of composites of high strength efficiency index. The addition of graphene particles and the formation of graphite agglomerates significantly decreased electrical resistivity of the MOC matrix which was originally characterized by low electrical conductivity

Physical Properties Investigation of Reduced Graphene Oxide Thin Films Prepared by Material Inkjet Printing

The article is focused on the study of the optical properties of inkjet-printed graphene oxide (GO) layers by spectroscopic ellipsometry. Due to its unique optical and electrical properties, GO can be used as, for example, a transparent and flexible electrode material in organic and printed electronics. Spectroscopic ellipsometry was used to characterize the optical response of the GO layer and its reduced form (rGO, obtainable, for example, by reduction of prepared layers by either annealing, UV radiation, or chemical reduction) in the visible range. The thicknesses of the layers were determined by a mechanical profilometer and used as an input parameter for optical modeling. Ellipsometric spectra were analyzed according to the dispersion model and the influence of the reduction of GO on optical constants is discussed. Thus, detailed analysis of the ellipsometric data provides a unique tool for qualitative and also quantitative description of the optical properties of GO thin films for electronic applications