High Absorption Cross Section Research Articles

Novel high temperature tritium blanket designs for confined spaces in spherical tokamak fusion reactors

Tritium self-sufficiency is one of the fundamental challenges for commercially viable deuterium–tritium nuclear fusion power stations. The combination of key high temperature radiation shielding materials that possess dense, high neutron absorption cross-section, and moderation properties, and tritium breeding materials could involve interesting design spaces for the central column challenge in spherical tokamaks. Potential tungsten alloys can be used for two functions: radiation shielding and structural material, providing a new design space window for spherical tokamak central column breeding space. In this paper, we present two novel high temperature concepts for the inboard side of the breeder blanket in a confined space, such as a spherical tokamak. A tungsten–rhenium–hafnium-carbide lithium-based design was found to offer the best TBR given a parameter optimisation based on shielding and thermal requirements. A silicon-carbide lead-lithium breeder design was also investigated. The highest TBR was found to be 0.135 in a 3D neutronics calculation with a W-24.5Re-2HfC (structural and shielding, wt%), Li (90% Li-6 enriched breeder), and tungsten pentaboride (W2B5) (shielding) option. Although this TBR is lower than unity, it will contribute to the reactor’s global TBR.

Luminescent Terbium Probe for Time‐Resolved FRET and NSET Binding Assays with Quantum Dots and Gold Nanoparticles

AbstractTime‐gated or time‐resolved FRET (TR‐FRET) assays are important tools in biosensing, bioimaging, drug screening, and molecular diagnostics. Efficient TR‐FRET assays require stable lanthanide complexes with high absorption cross sections, high quantum yields, and long photoluminescence lifetimes. Owing to their challenging synthesis, such complexes are relatively rare and new components are of potential interest when developing TR‐FRET probes. Here, we evaluate the recently developed Tb complex CoraFluor‐1 concerning its analytical performance in terbium‐to‐quantum dot FRET and terbium‐to‐gold nanoparticle NSET assays using the prototypical biological recognition system of streptavidin and biotin. Biological binding was quantifiable at sub‐picomolar concentrations in small sample volumes, with broad applicability demonstrated across three commercial fluorescence plate readers used for time‐resolved, spectrally‐resolved, and clinical bioanalysis. Overall, CoraFluor‐1 provided excellent analytical performance as both FRET and NSET donor, validating its potential for developing new TR‐FRET probes for biosensing and bioimaging.

Azaacene Diradicals Based on Non-Kekulé Meta-Quinodimethane with Large Two-Photon Cross-Sections in the Infrared Spectral Region.

Non-Kekulé quinoidal azaacences m-A (1 a,b) were synthesized and compared to their para- and ortho-quinodimethane analogues. m-A display high diradical characters (1 b: y0 = 0.88) due to their meta-quinodimethane (m-QDM) topology. Electron paramagnetic, nuclear magnetic resonance spectroscopies and supraquantum interference device measurements in combination with quantum-chemical calculations revealed singlet ground states for m-A with singlet-triplet gaps ΔEST (0.13-0.25 kcal mol-1) and thermally populated triplet states. These non-Kekulé structures are over all void of zwitterionic character and possess record high two-photon absorption cross sections over a broad spectral range in the near-infrared.

Exploring Carbon Dots: Green Nanomaterials for Unconventional Lasing.

In recent years, the progress toward lighting miniaturization is focused on luminescent nanomaterials. Among them, fluorescent carbon dots (CDs) are receiving increasing attention thanks to their astonishing optical properties complemented by their intrinsic biocompatibility and low toxicity. The CDs can be easily dispersed in water, organic solvents or incorporated in polymeric matrices, preserving their emission properties. However, the relationship between their structural and optical properties is still not fully elucidated, motivating a consistent research effort for the comprehension of their features. Nevertheless, CDs demonstrate to be efficient gain materials for lasing, thanks to their high quantum yield (QY), emission tunability in the visible and near infrared (NIR) range, short lifetimes, and high absorption cross section, even if the synthetic reproducibility, the low reaction yield and the spectral width of the emission may limit their effective exploitation. This review summarizes the latest advancements in the investigation of the characteristic properties of CDs that make laser action possible, illustrating optical geometries for lasing and random lasing, both in solution and solid state, and the few currently demonstrated breakthroughs. While the journey toward their effective application is still long, the potential of CD-based laser sources is promising in various technological fields and futuristic perspectives will be discussed.

(Invited) Electronic Trap Characterization in QD Devices Using Impedance Analysis Techniques

Colloidal quantum dots (QDs) are semiconductor nanocrystals with dimensions in the range of tens of nanometers. They exhibit unique optical and electronic properties, such as a size-dependent band gap and high absorption cross-section. These properties make them attractive for optoelectronic applications such as photovoltaics, light-emitting diodes (LEDs), and photodetectors. However, QD optoelectronics pose significant challenges due to trap states, which mainly originate from the surface states of nanocrystals. Therefore, it is necessary to analyze the trap states of QDs to understand their electronic properties and optimize their performance in optoelectronic applications. With this understanding, we want to correlate the cause of the trap states with the chemical defect to design better passivation strategies.In this discussion, we will explore the principles of electronic trap analysis in colloidal quantum dots based on impedance analysis techniques as a complementary method to spectroscopy. We will provide examples of electronic trap analysis in PbS QD photovoltaics and InP QD LEDs to demonstrate the effectiveness of this approach. We can electrically probe the QD layers in the device using an impedance analyzer to analyze the energy level and density of trap states. By combining chemical analysis and a theoretical approach with this technique, we attempted to correlate the trap states and chemical defects.

The Effect of Burnable Poison Np-237 on the Conceptual Design of the GFR-2400 MWt Using MCANDLE Burnup Strategy

This study was used to design the Gas-cooled Fast Reactor (GFR) with 2400 MWt power as well as to implement a modified CANDLE (MCANDLE) burning strategy. Metallic uranium with Neptunium-237 at a concentration of 1% to 10% was used as burnable poison in the fuel while helium was applied as a coolant. Neptunium has been produced in conventional reactors by the decay product of plutonium obtained from U-238. This isotope has a relatively high absorption cross-section. As a nuclear waste, it is very useful to utilize as a burnable poison to reduce waste in the future and extend reactor operation lifetime with negligible reactivity. Moreover, the reactor was designed to operate for 100 years of burnup. Nuclear Fuel cell level calculations were conducted using the PIJ module and the reactor core was analyzed using the CITATION module contained in the SRAC. The core height was found to be 420 cm while the diameter was 300 cm and it was designed to have a refueling period of ten years. The survey parameters evaluated include burnup level, factor multiplication, conversion ratio, atomic density, and power distribution. The calculation conducted at the fuel cell level showed that the maximum value in the 76th year for the infinite multiplication factor was 1.30097. It was also discovered that the reactor core for the effective multiplication factor parameter with a fuel fraction of 55% was 1.094 without the addition of burnable poison.

Online headspace monitoring of volatile organic compounds using proton transfer reaction-mass spectrometry: Application to the multiphase atmospheric fate of 2,4-hexadienedial

Chemical processes in clouds have been suggested to contribute significantly to the mass of organic aerosol particles in the atmosphere. Experimental and theoretical evidence suggest that organic mass production in clouds can be substantial and depends on the concentration of organic precursor compounds available in the gas phase. The present study aims at studying the aqueous phase reactivity of one of these overlooked precursors, i.e. 2,4-hexadienedial, an important and toxic intermediate in the atmospheric oxidation of aromatic species. Cautious synthesis and purification of 2,4-hexadienedial was performed. Its effective Henry's law constant was measured using a new simple and fast method based on online flow-injection analysis. The reactivity of 2,4-hexadienedial in the aqueous phase relevant to atmospheric conditions was studied, including hydrate formation, photolysis, ∙OH- and SO4∙--oxidation as well as reaction with NH3. The results revealed a low hydration constant compared to other dicarbonyls (Khyd1 = 7 × 10−2) and no dihydrate formation, indicating in an intermediate solubility (KH = 1.0 × 104 M atm−1) and high absorption cross sections (σ278nm > 10−16 cm2 molecule−1). Compared to its gas phase photolysis, its aqueous phase photolysis showed low quantum yields (Φ290–380nm = 0.9 %), and a significant red shift of the absorbance maximum, leading to a fast aqueous photolysis kinetics (Jaq,atm = 8.7 × 10−5 s−1) under atmospheric solar radiation, but no triplet state formation was detected. Radical oxidation experiments revealed extremely rapid oxidation kinetics (k∙OH = 1.10 × 1010 M−1 s−1 and kSO4∙- = 1.4 × 109 M−1 s−1) driven by fast addition of the radicals to the unsaturated bonds. In contrast, the reaction with aqueous NH3 (kNH3 = 2.6 × 10−3 M−1 s−1) was found slower than glyoxal and 2-butenedial, likely due to the hyperconjugation of 2,4-hexadienedial. Using these new data complemented with assumed aqueous phase kinetics (for NO3, 3C* and 1O2 reactions) and previous gas-phase kinetic ones, the multiphase atmospheric fate of 2,4-hexadienedial was established under atmospheric conditions reported from previous field measurements and models. The results revealed a short day lifetime (∼1 h) and a long night lifetime (>12 h). It was shown that daytime atmospheric chemistry of 2,4-hexadienedial can be influenced by aqueous-phase reactivity during cloud events, up to ∼50 % under thick cloud conditions (Liquid Water Content >2000 g/m3), indicating that even a compound of intermediate solubility can be strongly affected by condensed-phase reactivity. Besides its fast aqueous phase reactivity towards ∙OH and photolysis, its daytime condensed-phase reactivity may be driven by reactions with dissolved triplet states (3C*), up to 35 %, highlighting the need to study further the kinetics, the nature and concentrations of dissolved 3C* under various atmospheric conditions. In addition, the molecular properties and atmospheric behavior of 2,4-hexadienedial were found different from those of glyoxal and 2-butenedial, highlighting the need for detailed atmospheric reactivity studies of polyfunctional compounds, in particular unsaturated compounds.

Numerical study of near-field radiative heat transfer between bio-inspired spiny particles

The spine-like structure appears on some smooth organisms and has a high light absorption cross-section. Inspired by the spiny structure in the nature, this study establishes models of solid and hollow spiny particles. The effects of spine cross-section size, uniform and nonuniform spine distribution, hollow size, gap, and spine dislocation on near-field radiative heat transfer of spiny particles are investigated based on the thermal discrete dipole approximations method. The spectral radiative conductance and volumetric net power distribution are obtained. The results indicate that the coupling of localized surface phonons between two particles is affected by spine cross-section size and spine distribution. Near-field radiative heat transfer of spiny particles is enhanced maximumly when the frequencies are slightly lower than the resonance frequency of smooth particles. The peak of the spectral conductance is red-shifted and decreases with the increase of hollow size. The uniformity of volumetric power absorbed distribution increases and the variation of the relative spectral conductance decreases with increasing gap. The influence of two particles’ spine dislocation on near-field radiative heat transfer and volumetric power absorbed distribution is not obvious.

Effectiveness of green-synthesized nickel-doped calcium ferrite nanoparticles in the X-ray/gamma radiation shielding applications

Nanoparticles comprising calcium ferrite doped with Nickel within a concentration range of 10 to 50 mol% were successfully produced using a solution combustion technique, employing neem leaf extract as a reducing agent. The subsequent calcination process at 500 °C validated the formation of orthorhombic calcium ferrite, featuring distinct Bragg reflections indicative of Nickel doping. An analysis via scanning electron microscopy (SEM) affirmed the presence of irregularly shaped nanoparticles with pores and voids within their structure. The optical energy band gap, determined through Wood and Tauc’s relation, ranged from 2.89 to 2.97 eV. Notably, an increase in Nickel substitution was found to correlate with an increase in the energy band gap and a reduction in crystallite size. The research extensively evaluated the nanoparticles’ efficacy in radiation protection, encompassing parameters such as mass attenuation coefficient, mean free path, half-value layer, and effective atomic number. The mass attenuation coefficient is found to be 0.05353 cm2g−1 for 40 mol% at 1332 KeV. EABF is found to be large for 40 mol% at 0.89 MeV energy. Likewise, 50 mol% has a high Neutron absorption cross section (σab) which is 1.5(barn). Also, the bremsstrahlung dose rate is found to be 1.35 (R/h)*103, at 1.511 MeV.Additionally, the study comprehensively explored variations in the energy-absorbing buildup factor across diverse energy ranges, taking into account the Nickel concentration within the calcium ferrite nanoparticles. This aspect holds significant importance in the field of radiation dosimetry, particularly in applications related to neutron shielding and bremsstrahlung radiation.

Growth and Characterization of Yb: CALYGLO Crystal for Ultrashort Pulse Laser Applications

Yb:CALYGLO crystals with a dopant concentration of 5 at.% were successfully grown using the Czochralski method. The crystal samples were extensively studied to analyze their structure, room temperature and low temperature spectra, and laser properties. The highest absorption cross-section at 977 nm was calculated to be 1.83 × 10−20 cm2 for σ polarization and 5.32 × 10−20 cm2 for π polarization. Similarly, the emission cross-section was determined to be 1.38 × 10−20 cm2 at 980 nm for σ polarization and 2.28 × 10−20 cm2 at 981 nm for π polarization, with a full width at half maximum (FWHM) of 50.3 nm and 89.5 nm, respectively. The fluorescence lifetime of the 5 at.% Yb:CALYGLO crystal at 2F5/2 was measured to be 1.10 ms. Additionally, gain cross-sections were calculated for different β values. In the continuous laser experiment, the crystal demonstrated a laser output of 20.15 W at 1057 nm, with a slope efficiency of 53.3%. These experimental findings indicate that the lattice of Y3+ in the crystal is partially replaced by Lu3+ and Gd3+, resulting in a broader spectrum. Consequently, this crystal shows promising potential as a gain medium for ultrashort pulse laser crystals.

Thieno[3,2-b]thiophene-based bridged BODIPY dimers: synthesis, electrochemistry, and one- and two-photon photophysical properties.

Four BODIPY dyes (6a-6d) with electron-donating or electron-withdrawing groups at the meso-position were synthesized by the Sonogashira coupling reaction of 2,5-diethynylthieno[3,2-b]thiophene with mono-iodo-BODIPY moieties. All compounds were fully characterized by 1H NMR and MALDI-TOF MS. Their photophysical and electrochemical properties were studied by UV-visible absorption spectroscopy, steady-state and time-resolved fluorescence spectroscopy, two-photon excitation spectroscopy and cyclic voltammetry. These conjugated dyes exhibit interesting photophysical properties such as a high molar extinction coefficient, large Stokes shift and high two-photon absorption cross section σ2.

Study on damage of Gd2O3-CeO2 under electronic energy loss: comparison between bulk-like and nanostructure.

To understand the physical phenomena responsible for radiation damage of the materials used in nuclear reactors, and thus study their operation life and/or efficiency, it is required to simulate the conditions by exposing the materials to energetic ions. Ceria (CeO2) has been proposed as one of the inert matrices for the transmutation of minor actinides in the futuristic inert matrix fuel (IMF) concept. The inert matrix should also contain burnable poison to compensate for the initial reactivity of fuel. In this context, gadolinium (Gd) is an excellent burnable poison with a high neutron absorption cross-section. In view of this, Gd2O3-CeO2 nano-powders were synthesized and sintered at 800 °C and 1300 °C to obtain different grain sizes and morphologies. FESEM and TEM were carried out to study the grain size of pristine pellets. The sintered pellets were irradiated with 80-MeV Ag ions (electronic energy loss (Se) regime) at room temperature to emulate the effect of fission fragments. For analysis of the effect of grain size on the irradiation-induced structural degradation at different fluences, GIXRD and Raman spectroscopy were performed. Significantly large damage has been observed for the smaller grain-sized samples (sintered at 800 °C) as compared to the large grain-sized sample (sintered at 1300 °C). Neither of the samples amorphized under the present experimental conditions as indicated by the presence of the Raman-active T2g mode (centred at 462 cm-1) and all the XRD peaks of fluorite cubic structure up to the highest fluence employed (1 × 1014 ions cm-2). X-ray photoelectron spectroscopy results demonstrate that Ce4+ to Ce3+ and vacancy-related isolated clusters are the main defects produced in the systems. The radiation tolerance behaviour of the samples is understood with the help of thermal spike simulation, which indicates higher transient lattice temperatures with longer duration in the smaller grain-sized sample upon irradiation. Gd-doped ceria thus possesses good radiation stability in the Se regime, indicating its potential for application in IMFs.

Enhancement of the optical properties of a Dy3+:Sr3Gd2(BO3)4 crystal by Ca2+ co-doping

In this work, polycrystalline Dy3+:(Sr1-xCax)3Gd2(BO3)4 (x = 0–0.9) compounds doped with different concentrations of Ca2+ were synthesized by solid-state reaction. On the basis of their structural and spectral data, the optimal Ca2+ ions doping concentration of 60 at.% was determined. Then the Dy3+:(Sr0.4Ca0.6)3Gd2(BO3)4 crystal was obtained by the Czochralski (Cz) method. The crystal has a relatively high absorption cross-section at 453 nm, which is 0.98 × 10−21 cm2 (E//c) with a full width at half maximum (FWHM) of 9 nm (E//c). The maximum emission cross-section of the 4F9/2 → 6H13/2 transition at 576 nm is 5.62 × 10−21 cm2 (E//c) with a FWHM of 14 nm. The fluorescence quantum efficiency is 52.5 %. Compared with the Dy3+:Sr3Gd2(BO3)4 crystal, the emission cross-section and fluorescence quantum efficiency of the Dy3+:(Sr0.4Ca0.6)3Gd2(BO3)4 crystal have been significantly improved. These further increase the possibility of the crystal emitting a yellow laser.

Highly Efficient MAPbI3-Based Quantum Dots Exhibiting Unusual Nonblinking Single Photon Emission at Room Temperature.

Highly emissive semiconductor nanocrystals, or so-called quantum dots (QDs) possess a variety of applications from displays and biology labeling, to quantum communication and modern security. Though ensembles of QDs have already shown very high photoluminescent quantum yields (PLQYs) and have been widely utilized in current optoelectronic products, QDs that exhibit high absorption cross-section, high emission intensity, and, most important, nonblinking behavior at single-dot level have long been desired and not yet realized at room temperature. In this work, infrared-emissive MAPbI3-based halide perovskite QDs is demonstrated. These QDs not only show a ≈100% PLQY at the ensemble level but also, surprisingly, at the single-dot level, display an extra-large absorption cross-section up to 1.80 × 10-12 cm2 and non-blinking single photon emission with a high single photon purity of 95.3%, a unique property that is extremely rare among all types of quantum emitters operated at room temperature. An in-depth analysis indicates that neither trion formation nor band-edge carrier trapping is observed in MAPbI3 QDs, resulting in the suppression of intensity blinking and lifetime blinking. Fluence-dependent transient absorption measurements reveal that the coexistence of non-blinking behavior and high single photon purity in these perovskite QDs results from a significant repulsive exciton-exciton interaction, which suppresses the formation of biexciton, and thus greatly reduces photocharging. The robustness of these QDs is confirmed by their excellent stability under continuous 1 h electron irradiation in high-resolution transmission electron microscope inspection. It is believed that these results mark an important milestone in realizing nonblinking single photon emission in semiconductor QDs.

Density functional study on the mechanics, thermodynamics, and H diffusion mechanism of LiH

LiH is valued by researchers and engineers for its high-temperature resistance, high strength, high hydrogen storage capacity of up to 12.6 wt%, and high neutron absorption cross section. However, sintering and application of this material are difficult. Lithium hydride is a highly effective neutron shielding material. The neutron shielding ability of lithium hydride is directly affected by the homogeneity of the total amount and distribution of hydrogen. The heat migration of hydrogen reduces the neutron shielding effectiveness of lithium hydride. It is critical to forecast H's diffusion behavior. The diffusion coefficient is a critical metric for determining the diffusion efficiency. As a result, the stability, electronic structure, and bonding properties of LiH, LiOH, and H entering the tetrahedral interstitial sites of LiH were calculated using first principles based on density functional theory (DFT). The elastic modulus of the system was also examined to find the lowest thermal conductivity, and some thermodynamic parameters were derived by calculating LiH phonons. Finally, static calculations were used to determine the diffusion coefficient and diffusion activation energy of H in the LiH solid solution. The results revealed that the addition of H altered the characteristics of the LiH semiconductor, giving it metallic features. The lowest thermal conductivity of the LiH system was 2.9. W·m−1 K−1. The diffusion coefficient was D=(2.638×10−2cm2/s)exp(−5.811×10−3cal/KBT). The activation energy for diffusion was 0.252 eV. The diffusion coefficients, elastic constants, and lattice parameters all corresponded well with previously published results. The density functional theory was employed to study the material's system energy and electrical structure, and the microscopic migratory behavior of hydrogen was predicted theoretically. The calculation of the lowest thermal conductivity provided a reference for the screening of ceramic materials.

Three-Photon Infrared Stimulation of Endogenous Neuroreceptors in Vivo.

To interrogate neural circuits and crack their codes, in vivo brain activity imaging must be combined with spatiotemporally precise stimulation in three dimensions using genetic or pharmacological specificity. This challenge requires deep penetration and focusing as provided by infrared light and multiphoton excitation, and has promoted two-photon photopharmacology and optogenetics. However, three-photon brain stimulation in vivo remains to be demonstrated. We report the regulation of neuronal activity in zebrafish larvae by three-photon excitation of a photoswitchable muscarinic agonist at 50 pM, a billion-fold lower concentration than used for uncaging, and with mid-infrared light of 1560 nm, the longest reported photoswitch wavelength. Robust, physiologically relevant photoresponses allow modulating brain activity in wild-type animals with spatiotemporal and pharmacological precision. Computational calculations predict that azobenzene-based ligands have high three-photon absorption cross-section and can be used directly with pulsed infrared light. The expansion of three-photon pharmacology will deeply impact basic neurobiology and neuromodulation phototherapies.

Measurement of Mechanical Behavior of 11B-Enriched MgB2 Wire Using a Pulsed Neutron Source

MgB2 represents a hexagonal superconductive material renowned for its straightforward composition, which has facilitated the development of cost-effective practical wires. Its capacity to function at temperatures as low as liquid hydrogen (LH2) has made it a prominent candidate as wire material for the coils of next-generation fusion reactors. Much like other superconducting wires, a prevalent issue arises when these wires are employed in coils, wherein electromagnetic forces induce tensile stress and strain within the wire. This, in turn, diminishes the critical current, which is the maximum current capable of flowing within the generated magnetic field and strain. The techniques and methods for accurately measuring the actual strain on the filaments are of paramount importance. While strain measurements have been conducted with synchrotron radiation and neutrons for other practical wires in the past, no such measurements have been undertaken for MgB2. Presumably, this lack of measurement is attributed to its relatively greater thickness, making it less suitable for synchrotron radiation measurements. Additionally, the high absorption cross-section of the included boron-10 poses challenges in obtaining elastic scattering data for neutron measurements. In response, we fabricated a wire enriched with boron-11, an isotope with a smaller neutron absorption cross-section. We then embarked on the endeavor to measure its strain under tensile loading using pulsed neutrons. Consequently, we succeeded in obtaining changes in the lattice constant under tensile loading through Rietveld analysis. This marks the inaugural instance of strain measurement on an MgB2 filament, signifying a significant milestone in superconductivity research.

Gold Nanorod/Titanium Dioxide Hybrid Nanoparticles for Plasmon-Enhanced Near-Infrared Photoproduction of Hydroxyl Radicals and Photodynamic Therapy.

Gold nanoparticles, such as nanorods (AuNRs), present exceptionally high absorption cross sections that can be tuned to the near-infrared (NIR), the optimal window for light penetration in biological tissues. This makes them valuable photosensitizers for the treatment of cancer using photothermal therapy, where absorbed light energy is converted into heat. In addition, there is a strong interest in using hot electron carriers generated in AuNRs by NIR irradiation to produce cytotoxic radical oxygen species in order to enhance the efficiency of the phototherapy. Here, we show that hybrid nanoparticles composed of AuNRs with TiO2 deposited at their extremities are efficient sensitizers to produce hydroxyl radical species under NIR irradiation. We attribute this phenomenon to the transfer of hot electrons generated from the plasmon excitation in AuNR to the TiO2 tips, followed by reduction of dioxygen. We then functionalize these hybrid AuNR/TiO2 nanoparticles with block poly(ethylene glycol)-phosphonate polymer ligands to stabilize them in a physiological medium. We finally demonstrate that the photodynamic effect induces cell death upon irradiation with a greater efficiency than the photothermal effect alone.

Synthesis and Thermal Oxidation Resistance of Boron-Rich Boron-Carbide Material.

A boron-rich boron-carbide material (B4+δC) was synthesized by spark plasma sintering of a ball-milled mixture of high-purity boron powder and graphitic carbon at a pressure of 7 MPa and a temperature of 1930 °C. This high-pressure, high-temperature synthesized material was recovered and characterized by X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, Vickers hardness measurements, and thermal oxidation studies. The X-ray diffraction studies revealed a single-phase rhombohedral structure (space group R-3m) with lattice parameters in hexagonal representation as a = 5.609 ± 0.007 Å and c = 12.082 ± 0.02 Å. The experimental lattice parameters result in a value of δ = 0.55, or the composition of the synthesized compound as B4.55C. The high-resolution scans of boron binding energy reveal the existence of a B-C bond at 188.5 eV. Raman spectroscopy reveals the existence of a 386 cm-1 vibrational mode representative of C-B-B linear chain formation due to excess boron in the lattice. The measured Vickers microhardness at a load of 200 gf shows a high hardness value of 33.8 ± 2.3 GPa. Thermal gravimetric studies on B4.55C were conducted at a temperature of 1300 °C in a compressed dry air environment, and its behavior is compared to other high-temperature ceramic materials such as high-entropy transition metal boride. The high neutron absorption cross section, high melting point, high mechanical strength, and thermal oxidation resistance make this material ideal for applications in extreme environments.

Light trapping using a dimer of spherical nanoparticles based on titanium nitride for plasmonic solar cells

Light-trapping mechanisms with plasmonics are an excellent way to increase the efficiency of photovoltaics. Plasmonic dimer-shaped nanoparticles are effective in light absorption and scatterings, and there is hardly any research on dimer TiN nanoparticle-based PV. This paper demonstrated that titanium nitride could be a suitable substitute for other plasmonic materials in the visible and near-infrared spectrum. We designed a TiN-based spherical dimer plasmonic nanoparticle for photovoltaic applications. We conducted comparison analyses with the metals Ag, Au, and Al to ascertain the performance of TiN as a plasmonic material. Silicon had an average absorption power of ∼19%, and after incorporating TiN nanoparticles, the average absorbed power increased significantly to ∼75% over the whole spectral range. TiN dimer nanoparticle had the highest absorption cross-section, Q ab value ∼6.2 W/m2 greater than Ag, Au, and Al had a fraction of light scattered into the substrate value greater than Au, Al and comparable to Ag. TiN dimer exhibited better absorption enhancement, g for the whole spectral range than Ag, Au, and Al dimers for a radius of 15 nm with a peak value greater than 1. The maximum optical absorption efficiency of the plasmonic TiN nanostructures was ∼ 35.46%.