Amorphous Selenium Research Articles

SnSe nanocomposite chemically-bonded with carbon-coating as an anode material for K-ion batteries with outstanding capacity and cyclability

• A chemically bonded, nanosize SnSe@C composite is fabricated by a scalable method. • The chemically bonded SnSe@C nanocomposite anode is explored for use in K-ion batteries. • The use of amorphous carbon and selenium can significantly suppress the volume expansion of SnSe. • The chemically bonded SnSe@C nanocomposite exhibits excellent cyclability and rate capability. The use of SnSe alloys as anode materials in potassium-ion batteries (PIBs) has recently attracted considerable attention owing to the natural abundance of Sn and Se and the environmental friendliness, high theoretical capacity, and 2D layered structure of SnSe. However, due to the large volumetric change and severe pulverisation during potassiation and depotassiation, they exhibit poor cycling stability in PIBs. In this work, we fabricated a strongly chemically bonded SnSe@C nanocomposite using a simple two-step process consisting of a facile chemical reaction followed by high-energy ball milling. In addition, the introduction of amorphous carbon and selenium effectively suppressed the stress/strain originating from volume expansion during potassiation/depotassiation. The chemically bonded SnSe@C nanocomposite exhibited high initial discharge and charge capacities of 744.8 and 440.7 mAh g −1 , respectively. Even after 50 cycles, it retained a charge capacity of 401 mAh g −1 at 50 mA g −1 , with a coulombic efficiency (CE) of 99.6%. Even at high specific currents of 300 and 500 mA g −1 , the electrode maintained capacities of 270.7 and 203.4 mAh g −1 after 100 and 1000 cycles, respectively, and the CE was almost 100%. Furthermore, a SnSe@C/KFe[Fe(CN) 6 ·xH 2 O] full cell also showed superior cyclability and better rate capability. After 100 cycles, it retained a discharge capacity of 213.9 mAh g −1 at 200 mA g −1 . In addition, the phase transitions in the SnSe@C electrode during potassiation/depotassiation were investigated using ex-situ X-ray diffraction analysis. This work will provide an effective reference for Sn-Se alloy-based anodes for batteries to replace the lithium-ion batteries (LIBs).

The distribution and conversion of selenite and selenate with the bubbling of simulated flue gas in simulated WFGD slurry

Selenium is one of the hazardous trace elements emitted from coal-fired power plants. The distribution of selenium in Wet Flue Gas Desulfurization (WFGD) process is still unclear and even in controversial, impeding the development of selenium removal technologies. This research has found that the selenite in simulated slurry could be reduced by SO2 while selenate has not been affected. Characterization methods including X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) were used to provide an evidence that the product of the reduction reaction is amorphous elemental selenium. Meanwhile, the influences of other gaseous components, pH, temperature and S2O82− in simulated slurry has also been considered in this research. It is found that with the increase of SO2 concentration in flue gas, the reduction of selenite increased and the reduction reaction is an exothermic reaction. Meanwhile, the oxidation effect of S2O82− competes with the reduction effect of SO2. This study introduced the influence of flue gas into the research of the conversion of selenium in FGD slurry and indicate the effect of flue gas on the potential emission treatment techniques of selenium in FGD slurry.

Silver Antimony Sulfide Selenide Thin‐Film Solar Cells via Chemical Deposition

Silver antimony sulfide selenide (AgSbS1.3Se0.7) thin film forms from silver antimony sulfide (AgSbS2, 700 nm) and amorphous selenium (Se, 300 nm), both obtained via chemical deposition and heated in contact at 180 °C for 30 min in an argon ambient. The face‐centered cubic (fcc) structure of AgSbS2 (cuboargyrite) is maintained in AgSbS1.3Se0.7. The optical bandgap of 1.8 eV (direct forbidden) in AgSbS2 reduces to 1.47 eV in AgSbS1.3Se0.7 with an increase in the light‐generated current density from 19 to 29 mA cm−2. The photoconductivity in AgSbS1.3Se0.7 of 2 × 10−5 Ω−1 cm−1 is an order of magnitude higher than that in AgSbS2. A solar cell of SnO2:F/CdS(80 nm)/AgSbS1.3Se0.7(700 nm)/C‐Ag, produced by heating at 280 °C with the graphite (C) electrode applied, shows a conversion efficiency (η) of 0.65%, open‐circuit voltage (Voc) of 0.537 V, short‐circuit current density (Jsc) of 2.07 mA cm−2, and fill factor of 0.60. In AgSbS2 solar cell, η is of 0.54% with a Voc of 0.625 V. The merits of AgSbS1.3Se0.7 as a solar cell absorber and ways to increase the Jsc in the AgSbS1.3Se0.7 solar cell to match its JL are discussed.

Spectroscopic ellipsometry of amorphous Se superlattices

Superlattice structures have a variety of electrical and optical properties that allow for interesting applications like quantum cascade lasers and ultrasensitive photo-detectors. However, such structures require high-tech fabrication methods like molecular beam epitaxy, and this technology barrier means that these promising devices are not in widespread use. Using the simple method of rotational evaporation, we fabricated films with alternating multi-nanolayers of amorphous selenium (Se) and arsenic selenide (As2Se3). We investigated the optical properties of the individual materials, and the resulting multi-layer structure using spectroscopic ellipsometry. The results were modeled using Cody–Lorentz oscillators to obtain the refractive index (n) and extinction coefficient (k). The models showed the optical band gaps of Se and As2Se3 to be 1.97 and 1.69 eV, respectively. The absorption coefficient (α) of the multi-layer structure showed a series of five ‘steps’ in energy at 1.72, 1.82, 1.89, 1.97, and 2.04 eV. These are confirmed to stem from the transitions between confined quantum well levels due to the superlattice structure. In this way, the optical measurement using spectroscopic ellipsometry confirms the possibility of fabricating good quality nanostructutres using amorphous materials and rotational evaporation.

Engineering of a Blocking Layer Structure for Low-Lag Operation of the a-PbO-Based X-Ray Detector

Direct conversion flat panel detectors are of great significance to the field of medical X-ray imaging since they offer imaging performance and diagnostic capabilities not achievable with other methods. Currently, mammographic direct conversion detectors employ a layer of amorphous selenium (a-Se) photoconductor. Although its properties ideally fit the requirements of mammography, where “soft” X-rays are used, a-Se cannot be used in high-energy X-ray procedures. To extend the diagnostic capabilities of the direct conversion detectors, amorphous lead oxide (a-PbO) is proposed as an alternative photoconductor. It is a high effective atomic number material and thus has a higher X-ray stopping power over the wide X-ray energy range. a-PbO is, therefore, a suitable candidate for applications in radiography, fluoroscopy, and digital tomosynthesis. Here, we report on the development of a blocking structure with a polyimide (PI) layer needed to maintain low dark current at high electric fields. We demonstrate that a 1- $\mu \text{m}$ -thick PI blocking layer allows the operation of the detector at strong electric fields (≥10 V/ $\mu \text{m}$ ) while suppressing the dark current to an innocuous level (< 1 pA/mm2). It also improves temporal performance by reducing signal lag. No ghosting effect was observed at exposure rates up to 1 R/s; however, at high radiation levels, the detector’s sensitivity degraded. This degradation is not permanent as the detector restores its original sensitivity after several hours of rest in the dark without bias applied.

Diffusion, relaxation, and aging of liquid and amorphous selenium

Relaxation and aging rates of amorphous selenium and its undercooled melt are calculated by molecular dynamics based on an interaction model derived from density functional calculations. After a fast initial relaxation immediately following the quench, the decrease of diffusivity and the simultaneous increase of dynamic heterogeneity follow an exponential law given by defect annihilation. As observed previously in a Lennard-Jones glass, the non-Arrhenius aging of atomic volume and energy is determined by the time dependence of the diffusivity. The aging time is determined for long times by the diffusivity and diverges exponentially with decreasing temperature. Amorphous selenium differs from metallic glasses in that the breaking of covalent bonds is important for the long time decay of the intermediate self-scattering function (ISSF). Surprisingly for the temperatures investigated, aging of the relaxation times of the ISSF and the bond decay follow the aging of the diffusivity.

A Monolithic Amorphous-Selenium/CMOS Single-Photon-Counting X-Ray Detector

We report on the design and characterization of a monolithic single-photon-counting (SPC) X-ray detector integrating an amorphous semiconductor sensor. Our prototype combines amorphous selenium (a-Se), a well-known photoconductor, with a CMOS readout integrated circuit (ROIC) containing two 26×196 arrays of single-energy-threshold pixels. We achieve high spatial resolution for capturing single 60-keV photons by implementing 11.4- μ\textm-pitch pixels and by integrating a 70- μ\textm-thick a-Se sensor on the ROIC. We present experimental SPC results using a mono-energetic 60-keV radioactive source. Our results also suggest that our prototype a-Se/CMOS detector leverages the small-pixel effect (SPE) due to the large ratio of a-Se thickness to pixel pitch. This effect could overcome the slow inherent transient response of a-Se for high count rate X-ray diagnostic applications like mammography.

Centimeter‐Sized Molecular Perovskite Crystal for Efficient X‐Ray Detection

AbstractMolecular perovskites have demonstrated great potential for ferroelectrics and nonlinear optics; however, their charge transport properties for optoelectronics have rarely been explored. Here, understanding of charge transport behavior of molecular perovskite under X‐ray excitation based on centimeter‐scale TMCM‐CdCl3 (TMCM+, trimethylchloromethyl ammonium) single crystal is demonstrated. The crystal is fabricated from an aqueous solution and exhibits a large bandgap of 5.51 eV, with the valence band maximum mainly dominated by the Cl‐p/Cd‐d states and the conduction band minimum primarily by Cd‐s/Cl‐p states. Charge mobility exceeding 40 cm2 V−1 s−1 and mobility–lifetime (µτ) product on the order of 10−4 cm2 V−1 for the crystal are observed. These excellent optoelectronic properties translate to an efficient photoresponse under X‐ray excitation, with the sensitivity reaching 128.9 ± 4.64 µC Gyair−1 cm−2 [fivefold higher than that of the commercialized amorphous selenium (α‐Se)] and a low detection limit of 1.06 μC Gyair−1 s−1 (10 V bias). This work pioneers a superior metal‐based molecular perovskite single‐crystal based paradigm for optoelectronic investigation, which may lead to the discovery of a new generation of X‐ray detection and imaging materials.

Surface mobility in amorphous selenium and comparison with organic molecular glasses.

Surface diffusion is important for a broad range of chemical and physical processes that take place at the surfaces of amorphous solids, including surface crystallization. In this work, the temporal evolution of nanoholes is monitored with atomic force microscopy to quantify the surface dynamics of amorphous selenium. In molecular glasses, the surface diffusion coefficient has been shown to scale with the surface crystal growth rate (us) according to the power relation us ≈ Ds 0.87. In this study, we observe that the same power law applies to surface crystallization of amorphous selenium, a representative inorganic polymer glass. Our study shows that the surface diffusion coefficient can be used to quantitatively predict surface crystallization rates in a chemically diverse range of materials.

Zero-Dimensional Lead-Free FA3Bi2I9 Single Crystals for High-Performance X-ray Detection.

Direct X-ray detectors based on metal halide perovskites and their derivatives exhibit high sensitivity and low limit of detection (LoD). Compared with three-dimensional (3D) hybrid lead halide perovskites, low-dimensional A3Bi2I9 perovskite derivatives (A = Cs, Rb, NH4, CH3NH3(MA)) present better stability, greater environmental friendliness, and comparable X-ray detection performance. Here, we report FA3Bi2I9 (FA= CH(NH2)2) single crystals (SCs) as a new member of the A3Bi2I9 series for X-ray detection, which were prepared by the nucleation-controlled secondary solution constant temperature evaporation (SSCE) method. Centimeter-sized FA3Bi2I9 SCs show a full width at half-maximum (fwhm) of 0.0096°, which is superior to that of recently reported Cs3Bi2I9 (0.058°) and MA3Bi2I9 SCs (0.024°) obtained by inverse temperature crystallization (ITC). The as-grown FA3Bi2I9 SC shows a large resistivity of 7.8 × 1010 Ω cm and a high ion migration activation energy (Ea) of 0.56 eV, which can guarantee a low noise level and good operational stability under a large external bias. The FA3Bi2I9 SC detector exhibits a LoD of 0.2 μGyair s-1, a sensitivity of 598.1 μC Gyair -1 cm -2, and an X-ray detection efficiency of 33.5%, which are much better than those of the commercialized amorphous selenium detector. Results presented here will provide a new lead-free perovskite-type material to achieve green, sensitive, and stable X-ray detectors.

Monte Carlo Solution of High Electric Field Hole Transport Processes in Avalanche Amorphous Selenium.

Amorphous selenium lacks the structural long-range order present in crystalline solids. However, the stark similarity in the short-range order that exists across its allotropic forms, augmented with a shift to non-activated extended-state transport at high electric fields beyond the onset of impact ionization, allowed us to perform this theoretical study, which describes the high-field extended-state hole transport processes in amorphous selenium by modeling the band-transport lattice theory of its crystalline counterpart trigonal selenium. An in-house bulk Monte Carlo algorithm is employed to solve the semiclassical Boltzmann transport equation, providing microscopic insight to carrier trajectories and relaxation dynamics of these non-equilibrium “hot” holes in extended states. The extended-state hole–phonon interaction and the lack of long-range order in the amorphous phase is modeled as individual scattering processes, namely acoustic, polar and non-polar optical phonons, disorder and dipole scattering, and impact ionization gain, which is modeled using a power law Keldysh fit. We have used a non-parabolic approximation to the density functional theory calculated valence band density of states. To validate our transport model, we calculate and compare our time of flight mobility, impact ionization gain, ensemble energy and velocity, and high field hole energy distributions with experimental findings. We reached the conclusion that hot holes drift around in the direction perpendicular to the applied electric field and are subject to frequent acceleration/deceleration caused by the presence of high phonon, disorder, and impurity scattering. This leads to a certain determinism in the otherwise stochastic impact ionization phenomenon, as usually seen in elemental crystalline solids.

Understanding the Strength of the Selenium–Graphene Interfaces for Energy Storage Systems

We present comprehensive first-principles density functional theory (DFT) analyses of the interfacial strength and bonding mechanisms between crystalline and amorphous selenium (Se) with graphene (Gr), a promising duo for energy storage applications. Comparative interface analyses are presented on amorphous silicon (Si) with graphene and crystalline Se with a conventional aluminum (Al) current collector. The interface strengths of monoclinic Se (0.43 J m-2) and amorphous Si with graphene (0.41 J m-2) are similar in magnitude. While both materials (c-Se, a-Si) are bonded loosely by van der Waals (vdW) forces over graphene, interfacial electron exchange is higher for a-Si/graphene. This is further elaborated by comparing the potential energy step and charge transfer (Δq) across the graphene interfaces. The interface strength of c-Se on a 3D Al current collector is higher (0.99 J m-2), suggesting a stronger adhesion. Amorphous Se with graphene has comparable interface strength (0.34 J m-2), but electron exchange in this system is slightly distinct from monoclinic Se. The electronic characteristics and bonding mechanisms are different for monoclinic and amorphous Se with graphene as they activate graphene via surface charge doping divergently. The implications of these interfacial physicochemical attributes on electrode performance have been discussed. Our findings highlight the complex electrochemical phenomena in Se interfaced with graphene, which may profoundly differ from their "free" counterparts.

Cover Feature: Reactivity of Ionic Liquids: Reductive Effect of [C4C1im]BF4 to Form Particles of Red Amorphous Selenium and Bi2Se3 from Oxide Precursors (ChemistryOpen 2/2021)

The Cover Feature shows the correlation between the stability and reactivity of ionic liquids (ILs). Undercutting the maximum operating temperature (MOT) the IL initially is protected. Reaching the MOT, reactive species can be formed by thermal decomposition and functionality of the IL changes. Thus IL, actually used as a solvent, can become reactants. A current case study shows, that, exceeding the calculated MOT, reactive decomposition products of [C4C1im]BF4 lead to the reduction of the oxide precursor SeO2 and the formation of red amorphous selenium. Analyzing the gaseous species formed during the reaction, the reaction mechanism can be deduced similar to Riley oxidation. Thereby, but-1-ene, reacts with SeO2 to Se, H2O, and but-3-en-2-one. Concluding, the suitability of the single-source oxide precursor Bi2Se3O9 for the synthesis of Bi2Se3 is proven. More information can be found in the Full Paper by Monika Knorr et al.

Simulation and Experimental Validation of the Uniformity of Thermally Evaporated Amorphous Selenium Films for Large-Area Imaging and Radiation Detection Applications

Amorphous selenium is one of the best photoconductors with a wide range of applications, from its early use in the photocopy industry to its present application in X-ray imaging. Low melting point and high vapor pressure of amorphous selenium enable uniform and economical deposition of this photoconductive material up to few millimeters thick. However, there is a tradeoff between deposition rate and film uniformity. In this article, a thermal evaporation system for amorphous selenium deposition was developed. The system geometry was simulated to determine the optimized source–substrate throw distance for uniform film thickness of amorphous selenium (a-Se) on a substrate with up to 4-in diameter. Boat and crucible source configurations of equal volume (100 cc) were tested. The film was fabricated, characterized, and the uniformity and thickness were measured and compared with simulation results.

High-Performance X-ray Detector Based on Single-Crystal β-Ga2O3:Mg.

X-ray detection plays an important role in medical imaging, scientific research, and security inspection. Recently, the β-Ga2O3 single-crystal-based X-ray detector has attracted extensive attention due to its excellent intrinsic properties such as good absorption for X-ray photons, a high breakdown electric field, high stability, and low cost. However, developing a high-performance β-Ga2O3-based X-ray detector remains a challenge because of the large dark current and the high oxygen vacancy concentration in the crystals. In this paper, we report a high-performance Mg-doped β-Ga2O3 single-crystal-based X-ray detector with a sandwich structure. The reduced dark current enables the detector to have a high sensitivity of 338.9 μC Gy-1 cm-2 under 50 keV X-ray irradiation with a dose rate of 69.5 μGy/s. The sensitivity is 16-fold higher than that of the commercial amorphous selenium detector. Furthermore, the reduced oxygen vacancy concentration can improve the response speed (<0.2 s) of the detector. The present studies provide a promising method to obtain the high performances for the X-ray detector based on β-Ga2O3 single crystals.

Corrosion Protective Film Formation on Mg Alloys AZ 31 by Exposure to Dilute Selenite Solutions.

The study of protective film formation on Mg alloys by exposure to sodium selenite solutions was conducted. Anodic polarization studies, electrochemical impedance spectroscopy studies, morphological analysis, and Energy-dispersive X-ray spectroscopy were performed on AZ31 Mg alloy after coating treatment in different concentrations of sodium selenite. The corrosion resistance was improved by around 5 times compared with control. Improved resistance to localized corrosion was observed in the coatings treated by 5 mM or 10 mM sodium selenite. The protection mechanism was ascribed to the transformation of selenite to insoluble selenium, the formation of insoluble MgSeO3 hydrate, and polymerization of amorphous selenium.

Mechanism of rapid compression-induced melt crystallization in selenium

Amorphous selenium (Se) can be easily prepared by quenching the melt, which indicates that the Se possesses the good glass-forming ability. However, crystallization occurs after rapidly compressing the melt within about 20 ms. In this work, we investigate the mechanism of rapid compression-induced crystallization from Se melt. Compressing Se melt experiments are carried out at the following temperatures: 513, 523 and 533 K. The melt is rapidly compressed under 2.4 GPa for about 20 ms. Different holding times, i.e. 0, 30, 60 min after solidification are adopted. The samples are quenched to room temperature and then unloaded to ambient pressure. The X-ray diffraction analysis of the recovered sample indicates that the crystallization product is the &lt;i&gt;t&lt;/i&gt;-Se. It is found that with the prolongation of holding time, the grain size increases due to the continuous aggregation growth of crystal grains. By comparing with the isothermal crystallization products of amorphous Se and ultrafine Se powder, it is suggested that the rapid compression-induced solidification product should be &lt;i&gt;t&lt;/i&gt;-Se crystalline. The speculation that the solidification product is amorphous Se and it crystallizes in the cooling process does not hold true. The amorphous Se cannot be prepared through the rapid compression process on a millisecond scale. It is related to the thermal stability of amorphous Se under high pressure. It is reported that the dependence of crystallization temperature &lt;i&gt;T&lt;/i&gt;&lt;sub&gt;x&lt;/sub&gt; on pressure i.e. d&lt;i&gt;T&lt;/i&gt;&lt;sub&gt;x&lt;/sub&gt;/d&lt;i&gt;P&lt;/i&gt; for amorphous Se is about 40–50 K/GPa in a range of 0.1 MPa–1 GPa. However, the &lt;i&gt;T&lt;/i&gt;&lt;sub&gt;x&lt;/sub&gt; of amorphous Se is almost constant in a range of 2–6 GPa. It means that the thermal stability of amorphous Se against crystallization does not increase with increasing pressure after 2 GPa. In this work, the temperature of 513–533 K in the experiments is higher than the &lt;i&gt;T&lt;/i&gt;&lt;sub&gt;x&lt;/sub&gt; of amorphous Se. Therefore, the&lt;i&gt; t&lt;/i&gt;-Se crystal is the stable phase and amorphous Se is unstable. The Se melt tends to crystallize in the supercooled liquid state after rapid compression. It is interesting to investigate the mechanism of d&lt;i&gt;T&lt;/i&gt;&lt;sub&gt;x&lt;/sub&gt;/d&lt;i&gt;P&lt;/i&gt; curve discontinuous change at around 2 GPa in the future. Both the Se melt after rapid compression and the amorphous Se before crystallization are in supercooled liquid state. We speculate that high pressure may result in the microstructure transition in supercooled liquid state Se.

Study of Contrast-to-Noise Ratio performance of a Medipix3RX CdTe detector for low dose mammography imaging

This study compares detector performance through measurements of Contrast-to-Noise Ratio (CNR) of images obtained by a standard commercial X-ray mammography setup, using a flat panel detector with a 200 μm thick amorphous Selenium (a-Se) sensor, and a laboratory setup, using a Medipix3RX detector with a 1 mm thick Cadmium Telluride (CdTe) semiconductor sensor. The laboratory setup corresponds to the geometry and X-ray spectrum of the commercial setup. Dose calibrations are applied to ensure comparability of results between both systems. Detection of microcalcifications in breast tissue is crucial for early medical diagnosis of breast cancer development, and improvements in image quality or reduction in radiation dose significantly benefit the field of mammography imaging. The Medipix3RX CdTe detector has the potential to improve mammography imaging due to a combination of two features: a photon-counting detection scheme that allows for electronic noise rejection, integrated in a small pixel pitch of 55 μm; and the higher X-ray photon absorption efficiency of CdTe, compared to materials such as Silicon (Si) or Se, in the mammography energy range. The comparison between both systems shows better CdTe detector performance when imaging microcalcification structures with sizes between 240 μm and 540 μm. The Medipix3RX CdTe detector produces higher CNR values as compared to the a-Se system for the studied speck sizes, at equivalent doses, with up to 30% for 540 μm structures. For 240 μm size specks, the Medipix3RX CdTe detector has more than twice better CNR performance than a-Se, even for half the dose values. Our results motivate further research to exploit the potential of the Medipix3RX CdTe detector for clinical mammography implementations, due to the benefit of simultaneous radiation dose reduction and improved imaging performance.

A Roadmap for the Chalcogenide-graphene Composites Formation Under a Glassy Regime

Background: Nano-composite is an innovative material having nano in which fillers dispersed in a matrix. Typ-ically, the structure is a matrix- filler combination, where the fillers like particles, fibers, or fragments are surrounded and bound together as discrete units by the matrix. The term nano-composite encompasses a wide range of materials right from three dimensional metal matrix composites to two dimensional lamellar composites. Therefore, the physical, chemical and biological properties of nano materials differ from the properties of individual atoms and molecules or bulk matter. The chalcogenide – graphene composites in glassy regime is the growing novel research topic in the area of composite material science. It is obvious to interpret such materials different physicochemical mechanism. Objective: The key objective of this research work to explore the internal physicochemical mechanism of the chalcogenide – graphene composites under the glassy regime. Including the prime chalcogen alloying element selenium amorphous atomic structure and their fullerene like bonding nature. By accommodating the essential properties of the stacked layers of bilayer graphene. The diffusion, compression and dispersion of the bilayer graphene in selenium rich ternary (X(1-x-y)-Y(x)- Z(y) + GF (bilayer graphene); X = Se, Y = Semimetal or metalloid, Z = None metal) alloys under the complex regime on and after thermal melting process are addressed. Materials and Methods: To synthesize the composite materials the well-known melt quenched method had adopted. More-over, to interpret the amorphous selenium (Se8) chains and rings molecular structures we had used vista software with an available CIF data file. While to show the armchair and zig-zag bonds with bilayer graphene structure the nanotube modeler simulation software has used. Results: Outcomes of this study reveals the chalcogenide -graphene nano composite formation under a glassy regime changes the individual materials structural and other physical properties that is reflecting in different experimental evi-dences, therefore, the modified theoretical concepts for the different properties of such composite materials are interpreted in this study. Discussion: The dispersion and diffusion of the high stiff graphene bonds in low dimension chalcogen rich alloys has been interpreted based on their quadric thermal expansion behaviour. In addition to this, a possible bond angle modification in the formation of X(1-x-y)-Y(x)- Z(y) + GF composites are also addressed. To interpret the distinct optical property behavior of the formed X(1-x-y)-Y(x)- Z(y) + GF composites and parent chalcogenide glassy alloys a schematic model of the energy levels is also addressed. Conclusion: To make a better understating on the formation mechanism such composites, the diffusion and deformation of high stiff graphene σ and π bonds in a low dimension chalcogenide alloy basic mechanism are discussed on basis of novel “thermonic energy tunneling effect” concept, which could result in quadratic thermal expansion of graphene. Moreover, the structural unit modifications of such composite materials are described in terms of their bond angle modifications and in-fluence of the coordination defects. The energy levels suppression and creation of addition sub energy levels in such com-posite materials are discussed by adopting the viewpoint impact of the foreign alloying elements and surface π-plasmonic resonance between the graphene layers in the honeycomb band structure. Thus, this study has described various basic aspects of the chalcogenide system – bilayer graphene composites formation under a glassy regime.

Reactivity of Ionic Liquids: Reductive Effect of [C4 C1 im]BF4 to Form Particles of Red Amorphous Selenium and Bi2 Se3 from Oxide Precursors.

Temperature‐induced change in reactivity of the frequently used ionic liquid 1‐butyl‐3‐methylimidazolium tetrafluoroborate ([C4C1im]BF4) is presented as a prerequisite for the rational screening of reaction courses in material synthesis. [C4C1im]BF4 becomes active with oxidic precursor compounds in reduction reaction at ϑ≥200 °C, even without the addition of an external reducing agent. The reaction mechanism of forming red amorphous selenium from SeO2 is investigated as a model system and can be described similarly to the Riley oxidation. The reactive species but‐1‐ene, which is formed during the decomposition of [C4C1im]BF4, reacts with SeO2 and form but‐3‐en‐2‐one, water, and selenium. Elucidation of the mechanism was achieved by thermoanalytical investigations. The monotropic phase transition of selenium was analyzed by the differential scanning calorimetry. Beyond, the suitability of the single source oxide precursor Bi2Se3O9 for the synthesis of Bi2Se3 particles was confirmed. Identification, characterization of formed solids succeeded by using light microscopy, XRD, SEM, and EDX.