Narrow Results

This paper reports on the successful deposition of phosphorus (P)-doped n-type (p-C:P) carbon (C) films, and fabrication of n-C:P/p-Si cells by pulsed laser deposition (PLD) using graphite target at room temperature. The cells performances have been given in the dark I–V rectifying curve and I–V working curve under illumination when exposed to AM 1.5 illumination condition (100mW/cm², 25°C). The n-C:P/p-Si cell fabricated using a target with the amount of P by 7 weight percentages (Pwt%) shows the highest energy conversion efficiency η = 1.14% and fill factor FF = 41%. The quantum efficiency (QE) of the n-C:P/p-Si cells are observed to improve with Pwt%. The dependence of P content on the electrical and optical properties of the deposited films and the photovoltaic characteristics of the n-C:P/p-Si heterojunction solar cell are discussed.

The successful deposition of boron (B)-doped p-type (p-C:B) and phosphorous (P)-doped n-type (n-C:P) carbon (C) films, and fabrication of p-C:B on silicon (Si) substrate (p-C:B/n-Si) and n-C:P/p-Si cells by the technique of pulsed laser deposition (PLD) using graphite target is reported. The cells' performances are represented in the dark I–V rectifying curve and I–V working curve under illumination when exposed to AM 1.5 illumination condition (100 mW/cm², 25°C). The open circuit voltage (V_oc) and short circuit current density (J_sc) for p-C:B/n-Si are observed to vary from 230–250 mV and 1.5–2.2 mA/cm², respectively, and to vary from 215–265 mV and 7.5–10.5 mA/cm², respectively, for n-C:P/p-Si cells. The p-C:B/n-Si cell fabricated using the target with the amount of B by 3 Bwt% shows highest energy conversion efficiency, η = 0.20%, and fill factor, FF = 45%, while, the n-C:P/p-Si cell with the amount of P by 7 Pwt% shows highest energy conversion efficiency, η = 1.14%, and fill factor, FF = 41%. The quantum efficiencies (QE) of the p-C:B/n-Si and n-C:P/p-Si cells are observed to improve with Bwt% and Pwt%, respectively. The contributions of QE are suggested to be due to photon absorption by carbon layer in the lower wavelength region (below 750 nm) and Si substrates in the higher wavelength region. The dependence of B and P content on the electrical and optical properties of the deposited films, and the photovoltaic characteristics of the respective p-C:B/n-Si and n-C:P/p-Si heterojunction photovoltaic cells, are discussed.

This paper reports on the successful deposition of boron (B)-doped p-type (p-C:B) and phosphorus (P)-doped n-type (p-C:P) carbon (C) films, and the fabrication of p-C:B on silicon (Si) substrate (p-C:B/n-Si) and n-C:P/p-Si cells by a pulsed laser deposition (PLD) technique using a graphite target at room temperature. The boron and phosphorus atoms incorporated in the films were determined by X-ray photoelectron spectroscopy (XPS) to be in the range of 0.2–1.75 and 0.22–1.77 atomic percentages, respectively. The cells performances have been given in the dark I–V rectifying curve and I–V working curve under illumination when exposed to AM 1.5 illumination conditions (100 mW/cm², 25°C). The open circuit voltage (V_oc) and short circuit current density (J_sc) for p-C:B/n-Si are observed to vary from 230 to 250 mV and from 1.5 to 2.2 mA/cm², respectively; they vary from 215 to 265 mV and from 7.5 to 10.5 mA/cm², respectively, for n-C:P/p-Si cells. The p-C:B/n-Si cell fabricated using the target with the amount of boron by 3 weight percentages (Bwt%) showed the highest energy conversion efficiency, η = 0.20% and fill factor, FF = 45%. The n-C:P/p-Si cell fabricated using the target with the amount of 7 Pwt% showed the highest η = 1.14% and FF = 41%. The quantum efficiency (QE) of the p-C:B/n-Si and n-C:P/p-Si cells were observed to improve with Bwt% and Pwt%, respectively. The contribution of QE in the lower wavelength region (below 750 nm) may be due to photon absorption by the carbon layer, in the higher wavelength region it was due to the Si substrates. In this paper, the dependence of the boron and phosphorus content on the electrical and optical properties of the deposited films and the photovoltaic characteristics of the respective p-C:B/n-Si and n-C:P/p-Si heterojunction solar cells are discussed.

Crystalline cubic silicon carbide (3C-SiC) surface layers have been prepared by carbon-ion implantation into silicon (100) using a MEVVA ion source and subsequent annealing at 1250°C for 2 h. The obtained films have been characterized by SEM, XRD, and micro-Raman analysis. The effect of carbon-ion dose on the surface morphology of the ion-implanted samples has been investigated. Rectangular patterns are observed on the surfaces of carbon-ion-implanted silicon substrates. It is found that the amount of rectangular patterns increases with ion dose, suggesting the dependence of surface morphology on ion dose. The formation of rectangular patterns has been elucidated in this paper.

The Fe–C–H interaction near defects in iron structures was studied using qualitative structure calculations in the framework of the atom superposition and electron delocalization molecular orbital. Calculations were performed using three Fe clusters to simulate an edge dislocation, a divacancy; both in bcc iron and a stacking fault in an fcc iron structure. In all cases, the most stable location for C atom inside the clusters was determined. Therefore, H atom was approximated to a minimum energy region where the C atom resides. The total energy of the cluster decreases when the C atom is located near the defects zone. In addition, the presence of C in the defects zone makes no favorable H accumulation. The C acts as an expeller of H in a way that reduces the hydrogen Fe–Fe bonds weakening.

Recent research has shown that fly ash may catalyze the oxidation of elemental mercury and facilitate its removal. However, the nature of mercury-fly ash interaction is still unknown, and the mechanism of mercury retention in fly ash needs to be investigated more thoroughly. In this work, a fly ash from a coal-fired power plant is used to characterize the inorganic and organic constituents and then evaluate its mercury retention capacities. The as-received fly ash sample is mechanically sieved to obtain five size fractions. Their characteristics are examined by loss on ignition (LOI), scanning electron microscope (SEM), energy dispersive X-ray detector (EDX), X-ray diffraction (XRD), and Raman spectra. The results show that the unburned carbon (UBC) content and UBC structural ordering decrease with a decreasing particle size for the five ashes. The morphologies of different size fractions of as-received fly ash change from the glass microspheres to irregular shapes as the particle size increases, but there is no correlation between particle size and mineralogical compositions in each size fraction. The adsorption experimental studies show that the mercury-retention capacity of fly ash depends on the particle size, UBC, and the type of inorganic constituents. Mercury retention of the types of sp² carbon is similar to that of sp³ carbon.

The solution plasma process (SPP) has attracted considerable attention for the synthesis of carbon nanomaterials; the SPP uses electrical discharges generated directly by a bipolar pulsed power supply for various combinations of the solvents and solutes in the solution. However, the SPP requires high-temperature heat treatment for enhancing conductivity and exhibiting catalyst activity. Furthermore, the metal used as the electrode in the SPP is generally sputtered during discharge. This study presents the feasibility of reducing the heat-treatment step and solving the problem of sputtering of the metal electrodes by simply increasing the repetition frequency of the bipolar pulsed power. During synthesis, the pulse frequency acts as the graphitization catalyst. The enhancement of crystallinity was further confirmed by X-ray diffraction (XRD), Raman spectroscopy, and transmission electron microscopy (TEM). The findings of this study are expected to contribute toward research on improving the properties of carbon for various applications of the SPP synthesis methods.

This study examines the machinability of hybrid fiber metal laminates (HFML), which are made by nickel–chromium alloy (IN-625) metal-cored carbon (Ca)/aramid (Ar) fiber laminate using ultrasonic vibration-coupled microwire electrical discharge machining (UV-$\mu$WEDM). Since UV-$\mu$WEDM parameters significantly impact the erosion rate ($E_R$) and surface undulation ($S_U$), the main objective was to identify the optimal machining parameters. The input variables include the pulse on ($P_{\text{on}}$), pulse off ($P_{\text{off}}$), current ($I_C$), cutting inclination ($C_I$), and servo voltage ($S_V$) coupled with ultrasonic vibration (UV). The empirical findings show that the servo voltage ($S_V$) significantly impacts $E_R$ (73.93%) and $S_U$ (70.02%). The performance categorization order of significant influencing variable is $S_V>P_{\text{off}}>C_I>P_{\text{on}}>I_C$. The desirability interpretation generated the optimum setting for minimizing $S_U$ and maximizing $E_R$ is $P_{\text{on}}=8\mu$s, $P_{\text{off}}=14\mu$s, $S_V=50$V, $I_C=3$A, and $C_I=30^{\circ }$. Scanning electron microscopic (SEM) images were used to perform the micro-interlayer analysis on the machined surface. Moreover, creating an appropriate HFML is necessary to cut various shapes and sizes to satisfy the demands of diverse applications. 60% of components in the aerospace sector are reportedly rejected in real time due to dimension departure, poor surface finish, and damage found in the final assembly. Investigating the viability of cutting-edge machining techniques like UV-$\mu$WEDM is crucial to minimize damage and improve the quality of HFMLs.

We report on a number of new effects of self-organization at nanoscale, leading to creation of new functional nanomaterials, including carbon and carbon–metal nanotoroids and nanodiscs and self-assembling of magnetic nanoparticles into helices and chains. We also extensively used a new approach of biopattern nanoengineering to create DNA-based complexes with metal or CdSe/ZnS core-shell nanorods (22 × 4.5 nm) which possess strong linearly polarized photoluminescence due to unidirectional orientation of nanorods along DNA filaments. Optical, electrical, and topological (geometrical) properties of such complexes were investigated. This work is a result of a coherent effort (since 1980s) of a consortium of Russian research groups in Nano-technology (INTC: Interdisciplinary Nanotechnology Consortium) aimed at creating molecular electronic devices based on individual and collective properties of specially designed and fabricated nanoclusters.

Linear forms of carbon are important in a wide variety of applications, ranging from highly conducting interconnects to field emission materials. By methods of field ion microscopy (FIM) and mass-spectrometry, it was revealed that linear carbon chains were present at the surface of carbon fibers after high-voltage treatment. The carbon chains attached to the specimen tips were produced in situ in a field ion microscope by unraveling of nanofibers using low-temperature evaporation in electric fields of the order of 10¹¹ Vm^-1. The unraveling of graphite is possible due to the ultimate strength of the monoatomic carbon chain. The maximum force before failure of carbon chains at 0 K is 7.916 nN at a strain of 0.19 and the ideal tensile strength is equal to 252.1 GPa. Molecular dynamics simulations and high resolution FIM experiments are performed to assess the evaporation of atomic chains under high-field conditions. One can conclude that ions are field evaporated from a graphite surface initially in linear cluster forms, which decompose mostly into smaller atomic clusters and individual ions because of the ultrahigh-temperature excitation during unraveling.

A simple inexpensive wet chemical technique at room temperature to prepare hybrid structure of multiwalled carbon nanotubes (MWCNT) and cadmium sulfide (CdS) nanoparticles has been reported in this paper. Cadmium sulfide nanocrystals of average size 5 nm have been synthesized and attached with the surfaces of MWCNTs. The hybrid material is characterized by high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), and Raman spectroscopy. Interesting optical properties of the composite are revealed through UV–visible and photoluminescence (PL) spectroscopy. Significant blue-green PL emission covering a region from 450–600 nm wavelength has been observed when excited by UV radiation of 220–240 nm wavelength. Sharp emission peak has been obtained and this may find wide applications in optical sensors and optoelectronic devices.

In this work, the inorganic/organic a Carbon-Silica (C-S) nanocomposites in additional amorphous carbon matrix was successfully obtained through the sol–gel method, the two components are mixed in an effort to blend the best properties of both. The acquired C-S nanocomposites were characterized by X-ray diffraction (XRD). It was observed by Transmission Electronic Microscopy that nanoparticles with sizes from 14nm to 20nm. After heat treatment, we explore the electrical properties of the obtained C-S material. The current–voltage ($I$–$V$) and alternating current (ac) techniques in the temperature range (80–300K) was examined.

This paper reports the synthesis and characterization of ternary nanocomposites consisting of polyaniline (PANI), multiwalled carbon nanotubes (MWCNTs) and manganese dioxide (MnO₂) at different MWCNT–MnO₂ loadings. The composite electrical percolation threshold is investigated as well. The in situ nanocomposites were characterized by UV-visible, Fourier transform and Raman spectroscopy, thermogravimetric analysis, field emission scanning electron microscopy, and electrical conductivity measurements. The conductivity of the nanocomposite reached up to 78.79 Scm^-1 with 50 wt.% addition of MWCNT–MnO₂ with good conduction stability and reversibility. The percolation threshold of this nanocomposite was achieved at 0.5 wt.%. Using the scaling law of the percolation theory, it was found that the theoretical conductivity of the nanocomposite exhibited an exponential factor, (t) of 1.38 instead of the universal t value of 2.

In this study, silver orthophosphate@carbon layer (Ag₃PO₄@C) core/shell heterostructure photocatalyst was prepared for the first time. The results showed that a uniform carbon layer was formed around the Ag₃PO₄. By adjusting the hydrothermal fabrication parameters, the thickness of carbon layer could be easily controlled. Furthermore, the Ag₃PO₄@C had remarkable light absorption in the visible region. Photocatalytic tests displayed that the Ag₃PO₄@C heterostructures possessed a much higher degradation rate of phenol than pure Ag₃PO₄ under visible light. The enhanced photocatalytic activity could be attributed to high separation efficiency of photogenerated electrons and holes based on the synergistic effect between carbon as a sensitizer and Ag₃PO₄. Recycle tests showed that the Ag₃PO₄@C core/shell heterostructures maintained high stability over several cycles. The good stability could be attributed to the protection of insoluble carbon layer on the surfaces of Ag₃PO₄ crystals in aqueous solution.

The increasing energy crisis promotes the study on novel electrode materials with high performance for supercapacitive storage and energy conversion. Transition metal phosphates have been reported as a potential candidate due to the unique coordination and corresponding electronic structure. Herein, we adopted a facile method for preparing NaCoPO₄@C derived from a metal organic framework (MOF) as a bifunctional electrode. ZIF-67 was synthesized before a refluxing process with Na₂HPO₄ to form a precursor, which is transformed into the final product via calcination in different atmospheres. Specifically, the resultant NaCoPO₄@C exhibits a high specific capacitance of 1178.7Fg${}^{-1}$ at a current density of 1Ag${}^{-1}$ for a supercapacitor. An asymmetric supercapacitor (ASC) assembled with active carbon displays a high capacitance of 163.7Fg${}^{-1}$ at 1Ag${}^{-1}$. In addition, as an oxygen evolution reaction (OER) catalyst, the NaCoPO₄@C electrode requires only 299mV to drive a current density of 10mAcm${}^{-2}$. These results suggest that the rational design of MOF-derived NaCoPO₄@C provides a variety of practical applications in electrochemical energy conversion and storage.

Multi-element doped porous carbon materials are considered as one of the most promising electrode materials for supercapacitors due to their large specific surface area, abundant mesoporous structure, heteroatom doping and good conductivity. Herein, we propose a very simple and effective strategy to prepare nitrogen, sulfur co-doped hierarchical porous carbons (N-S-HPC) by one-step pyrolysis strategy. The effect of sole dopants as a precursor was a major factor in the transformation process. The optimized N-S-HPC-2 possesses a typical hierarchically porous framework (micropores, mesopores and macropores) with a large specific surface area (1284.87m² g${}^{-1})$ and N (4.63 atomic %), S (0.53 atomic %) doping. As a result, the N-S-HPC-2 exhibits excellent charge storage capacity with a high gravimetric capacitance of 360F g${}^{-1}$ (1 A g${}^{-1})$ in three-electrode systems and 178F g${}^{-1}$ in two-electrode system and long-term cycling life with 87% retention after 10,000 cycles in KOH electrolyte.

Nanofluids are promising in solar harvesting and solar thermal utilization. Ethylene glycol (EG) nanofluids have the advantages of high boiling point and low volatility, and therefore are highly desired in some circumstances. In this study, the solar harvesting and solar thermal conversion properties of EG were significantly enhanced by carbon chain nanostructures (CCNSs). The prepared CCNSs/EG nanofluids showed greater optical absorption compared to EG in the wavelength range from 250nm to 1400nm. The solar weighted absorption factor (Am) of the CCNSs/EG nanofluids was 95.9% at the mass fraction of 0.05 wt.%. The enhancement was 649.2% compared to that of EG. The photothermal conversion efficiency was determined to be 97.7% and the enhancement of 83.0% was achieved. An enhancement of 1.2% in thermal conductivity was also been observed. These enhancements can be ascribed to the special architectures of the CCNSs that provide fast transfer path for the generated heat.

Carbon quantum dots (C QDs) were synthesized using lemon juices as a precursor by hydrothermal method. The impact of C QDs on the biomass, density of spores, and morphology of Aspergillus oryzae (A. oryzae) was studied for the first time. The results revealed that C QDs had a graphite structure, and their average size was about 4.25nm. As a carbon source, C QDs were more beneficial to A. oryzae growth than glucose. It has been observed that C QDs worked as an activator to improve the yield of A. oryzae, and the biomass and density of spores of A. oryzae cultured with 15mg C QDs were about 1.46 and 2.00 times higher than that in control medium (without C QDs). Our work can give a new idea for improving the yield of A. oryzae or microorganisms and satisfy industrial requirements.

In this paper, carbon particles with micro- and nano-particle size were synthesized through a hydrothermal reaction of glucose, namely C-1(123.1 nm), C-2(229.2 nm), C-3(335.1 nm), C-4(456.2 nm) and C-5(534.0 nm) with distinct sizes. We utilized five size carbon particles as individual fillers into the EHS matrix materials to prepare composite eutectic phase change materials (C/EHS PCMs) by melt blending technique. The impact of carbon particle size on the dispersion stability and thermal properties of Na₂SO₄·10H₂O–Na₂HPO₄·12H₂O (EHS) phase change materials was investigated. Scanning electron microscopy (SEM) and dynamic light scattering (DLS) analysis were done to analyze the diameters of carbon particles. The cryogenic-scanning electron microscopy (Cryo-SEM) analysis indicated that the carbon particles resulted in modification in the morphology of the EHS. The results of in situ X-ray diffraction (XRD) and Fourier-transformed infrared (FTIR) analysis showed only simple physical mixing between carbon particles and EHS. It is shown that adding 0.2 wt.% C-2 can decrease the supercooling degree of EHS to 1.5°C. The cyclic stability of C/EHS varies significantly depending on the size of carbon particles. The thermal conductivity of EHS increased by 42.1%, 39.9%, 14.4%, 19.5%, and 18.8% with the addition of C-1, C-2, C-3, C-4, and C-5, respectively, at a mass fraction of 0.2%. The results of differential scanning calorimetry reveal that the incorporation of C-1, C-2, C-3, and C-4 into EHS leads to an enhancement of latent heat. The latent heat capacity of EHS with 0.2 wt.% C-2 is 243.4 J·g⁻¹, and after undergoing 500 cycles of solid-liquid phase transition, the latent heat remained above 200 J·g⁻¹. Through the comprehensive analysis, the C-2/EHS composite phase change material holds significant potential for advancing building insulation and solar energy storage technologies.