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Cataluminescence coupled with photo-assisted technology: a highly efficient metal-free gas sensor for carbon monoxide
摘要： With the development of green chemistry, metal-free nano-catalysts have gradually substituted metal-based materials, causing widespread concern among researchers in many fields, especially in cataluminescence sensing, because of their long-term stability, environmental friendliness as well as low costs. Besides the catalysts, the innovations of assistant technologies for cataluminescence are needed to enhance the oxidation reactivity of the gas molecules or catalytic efficiency of sensing materials. Although, there are some groups enhancing the cataluminescence reaction via various assistant technologies, the development of assistant technologies in cataluminescence sensors are still in their infancy, the design, effect mechanism and application are still stimulating challenges. Herein, with photodynamic assistant, fluorinated nanoscale hexagonal boron nitride is first employed as a metal-free catalyst to establish a novel cataluminescence method for detecting CO gases, and the cataluminescence reaction mechanism of CO is also investigated in details. Under the best conditions, the detection limit (3σ) of the CO concentration is 0.005 μg mL-1, which has been largely improved in cataluminescence methods. The realization of detection of CO from theory to practice thorough the method of cataluminescence is beneficial of the practical application of metal-free catalysts to detect CO rather than stay at the possibility to detect CO by the means of theoretical calculation only.
关键词： metal-free gas sensor,carbon monoxide,Cataluminescence,fluorinated hexagonal boron nitride,photo-assisted technology
更新于2025-09-11 14:15:04
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Coupling of deterministically activated quantum emitters in hexagonal boron nitride to plasmonic surface lattice resonances
摘要： The cooperative phenomena stemming from the radiation field-mediated coupling between individual quantum emitters are presently attracting broad interest for applications related to on-chip photonic quantum memories and long-range entanglement. Common to these applications is the generation of electro-magnetic modes over macroscopic distances. Much research, however, is still needed before such systems can be deployed in the form of practical devices, starting with the investigation of alternate physical platforms. Quantum emitters in two-dimensional (2D) systems provide an intriguing route because these materials can be adapted to arbitrarily shaped substrates to form hybrid systems wherein emitters are near-field-coupled to suitable optical modes. Here, we report a scalable coupling method allowing color center ensembles in a van der Waals material (hexagonal boron nitride) to couple to a delocalized high-quality plasmonic surface lattice resonance. This type of architecture is promising for photonic applications, especially given the ability of the hexagonal boron nitride emitters to operate as single-photon sources at room temperature.
关键词： coupling,strain,delocalization,defect,quantum emission,photoluminescence,surface plasmons,hexagonal boron nitride,2D materials,surface lattice resonance
更新于2025-09-11 14:15:04
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AIP Conference Proceedings [AIP Publishing 15th International Conference on Concentrator Photovoltaic Systems (CPV-15) - Fes, Morocco (25–27 March 2019)] 15th International Conference on Concentrator Photovoltaic Systems (CPV-15) - Fine line Al printing on narrow point contact opening for front side metallization
摘要： Aluminum (Al) screen-printed narrow fingers on textured passivated emitter and rear totally diffused (n-PERT) front junction Si solar cells are applied and investigated. Commercial Al paste is screen-printed on symmetric test structures with different Local Contact Opening (LCO) designs by varying the dot-to-dot distances and finger widths. Strong dependency of the metal-silicon saturation current density (J0-met) is found for the considered geometries. Narrow Al grid metallization induced emitter recombination current density can be decreased by optimizing the dot-dot distance. Best results of our test matrix were determined for an 80 μm dot-dot pitch, realizing J0-met values down to 649 fA/cm2 when using narrow fingers of 65 μm compared with the J0-met of 1100 fA/cm2 identified for a commercial Ag/Al paste. For dot-to-dot distances below 40 μm, common pattern of bifacial p-type PERC, fingers with widths exceeding 120 μm are needed to realize J0-met values below 400 fA/cm2. Additionally, the shape and size of the Al-Si alloy and p++ doping layer depth after firing are strongly affected by the combination of dot-to-dot distances and screen-printed finger widths.
关键词： point contact,Al,contact formation,n-type,n-PERT,screen printing,boron emitter
更新于2025-09-11 14:15:04
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Boron Nitride Nanotubes in Nanomedicine || Optical properties of boron nitride nanotubes: potential exploitation in nanomedicine
摘要： Nanotechnology is the ability and the art of exploiting nanometer-scale control on the size and the shape of a system, in order to obtain novel physicochemical properties. Chemical reactivity, optical response, and interactions with cells and tissues of nanotailored materials can be remarkably different from those of the bulk counterpart. The application of this flexibility and of the enormous potential that it brings along to the treatment, prevention, or diagnosis of diseases—that is, nanomedicine—is a novel opportunity that in spite of its young age is already representing a market valued at almost 80 billion USD in 2012 [1], with hundreds of nanomedicines and nanoformulations which are either approved or under clinical evaluation [2]. In the class of nanomaterials, boron nitride nanotubes (BNNTs) possess unique characteristics that make them particularly appealing. BNNTs are structural equivalents of carbon nanotubes (CNTs) with boron and nitrogen atoms replacing the carbon atoms of CNTs, and can be thought as a rolled sheet of hexagonal BN (h-BN) as depicted in Fig. 9.1a, b, and d. Despite their structural similarity with CNTs, they are comparable or superior to the latter in terms of several technologically relevant properties such as a thermal conductivity (at least in isotopically pure tubes) [3], thermal [4] and chemical [5] stability, piezoelectricity [6], and mechanical strength [7]. These peculiar advantages stem from the significant ionic component of the covalent bonds between B and N atoms.
关键词： Boron Nitride Nanotubes,Optical Properties,Nanotechnology,Nanomedicine
更新于2025-09-11 14:15:04
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Boron Nitride Nanotubes in Nanomedicine || Boron nitride nanotube films: preparation, properties, and implications for biology?applications
摘要： Boron nitride nanotubes (BNNTs) share the same structure as carbon nanotubes (CNTs), but have boron and nitrogen atoms sitting close to each other. Some properties of BNNTs are similar to their carbon counterparts, such as mechanical strength, thermal conductivity, and wettability. However, there are also many differences between them. BNNTs are insulators with a wide bandgap of about 6 eV, which is not sensitive to their diameter and chirality. Compared to CNTs, BNNTs are more thermally stable in air and, therefore, better candidates as fillers in metal/ceramic composites, field emitters, and thermal management materials at high temperatures. BNNTs show strong light emission at ～227 nm in the deep ultraviolet (DUV) region and are useful in optoelectronic, medical, data storage, and lithography applications. Isotopic 10BNNTs not only exhibit greatly improved thermal conductivity superior to that of CNTs, but also provide radiation shielding. Due to the electric polarization, BNNTs are piezoelectric and suitable for electromechanical devices on the nanoscale.
关键词： biology applications,Boron nitride nanotubes,properties,BNNT films,preparation
更新于2025-09-11 14:15:04
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B-doping and annealing on the properties of B and Ga co-doped ZnO films
摘要： Transparent conducting boron (B) and gallium (Ga) co-doped ZnO (BGZO) films were deposited by radio frequency (RF) magnetron sputtering. The influence of B-doping and annealing treatment on properties of BGZO films was investigated. The results indicate that all samples have hexagonal wurtzite structure with (002) preferential orientation and the film crystallinity is improved with increasing annealing temperature. The hall mobility of films increase and the carrier concentration decrease with the increasing of annealing temperature. The films also show red shift of the optical bandgap with the increasing of annealing temperature. The incorporation of B increases the thermal stability of electrical properties of the BGZO film.
关键词： ZnO,annealing,magnetron sputtering,boron
更新于2025-09-11 14:15:04
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Direct, transfer-free growth of large-area hexagonal boron nitride films by plasma-enhanced chemical film conversion (PECFC) of printable, solution-processed ammonia borane
摘要： Synthesis of large-area hexagonal boron nitride (h-BN) films for two-dimensional (2D) electronic applications typically requires high temperatures (~1000 oC) and catalytic metal substrates which necessitate transfer. Here, analogous to plasma-enhanced chemical vapor deposition, a non-thermal plasma is employed to create energetic and chemically-reactive states such as atomic hydrogen and convert a molecular precursor film to h-BN at temperatures as low as 500 oC directly on metal-free substrates – a process we term plasma-enhanced chemical film conversion (PECFC). Films containing ammonia borane as a precursor are prepared by a variety of solution processing methods including spray deposition, spin coating, and ink-jet printing, and reacted in a cold-wall reactor with a planar dielectric barrier discharge operated at atmospheric pressure in a background of argon or mixture of argon and hydrogen. Systematic characterization of the converted h-BN films by micro Raman spectroscopy shows that the minimum temperature for nucleation on silicon-based substrates can be lowered from 800 to 500 oC by the addition of a plasma. Furthermore, the crystalline domain size, as reflected by a decrease in the full-width-half-maximum, increased by more than 3 times (>40 cm-1 to ~13 cm-1). To demonstrate the potential of the h-BN films as a gate dielectric in 2D electronic devices, molybdenum disulfide field-effect transistors were fabricated and the field effect mobility was found to be improved by up to four times over silicon dioxide. Overall, PECFC allows h-BN films to be grown at lower temperatures and with improved crystallinity than CVD, directly on substrates suitable for electronic device fabrication.
关键词： two-dimensional (2D) material,plasma,chemical vapor deposition (CVD),boron nitride (BN)
更新于2025-09-11 14:15:04
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Point defects and dopants of boron arsenide from first-principles calculations: Donor compensation and doping asymmetry
摘要： We apply hybrid density functional theory calculations to identify the formation energies and thermodynamic charge transition levels of native point defects, common impurities, and shallow dopants in BAs. We find that AsB antisites, boron-related defects such as VB, BAs, and Bi-VB complexes, and antisite pairs are the dominant intrinsic defects. Native BAs is expected to exhibit p-type conduction due to the acceptor-type characteristics of VB and BAs. Among the common impurities we explored, we found that C substitutional defects and H interstitials have relatively low formation energies and are likely to contribute free holes. Interstitial hydrogen is surprisingly also found to be stable in the neutral charge state. BeB, SiAs, and GeAs are predicted to be excellent shallow acceptors with low ionization energy (<0.03 eV) and negligible compensation by other point defects considered here. On the other hand, donors such as SeAs, TeAs SiB, and GeB have a relatively large ionization energy ((cid:2)0.15 eV) and are likely to be passivated by native defects such as BAs and VB, as well as CAs, Hi, and HB. The hole and electron doping asymmetry originates from the heavy effective mass of the conduction band due to its boron orbital character, as well as from boron-related intrinsic defects that compensate donors.
关键词： dopants,donor compensation,doping asymmetry,first-principles calculations,boron arsenide,point defects
更新于2025-09-11 14:15:04
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Hydrogenation and Fluorination of 2D Boron Phosphide and Boron Arsenide: A Density Functional Theory Investigation
摘要： First-principles density functional theory calculations are performed to study the stability and electronic properties of hydrogenated and fluorinated two-dimensional sp3 boron phosphide (BP) and boron arsenide (BAs). As expected, the phonon dispersion spectrum and phonon density of states of hydrogenated and fluorinated BX (X = P, As) systems are found to be different, which can be attributed to the different masses of hydrogen and fluorine. Hydrogenated BX systems bear larger and indirect band gaps and are found to be different from fluorinated BX systems. These derivatives can be utilized in hydrogen storage applications and ultrafast electronic devices. Finally, we investigated the stability and electronic properties of stacked bilayers of functionalized BP. Interestingly, we found that these systems display strong interlayer interactions, which impart strong stability. In contrast with the electronic properties determined for the fluorinated/hydrogenated monolayers, we found that the electronic properties of these bilayers can finely be tuned to a narrow gap semiconductor, metallic or nearly semimetallic one by selecting a suitable arrangement of layers. Moreover, the nearly linear dispersion of the conduction band edge and the heavy-, light-hole bands are the interesting characteristics. Furthermore, the exceptional values of effective masses assure the fast electronic transport, making this material very attractive to construct electronic devices.
关键词： boron phosphide,boron arsenide,hydrogenation,fluorination,density functional theory,electronic properties,stability
更新于2025-09-10 09:29:36
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Structural and electrical properties of boron doped InSe single crystals
摘要： Structural and electrical properties of undoped, 0.1%, 0.5% and 1.8% boron doped InSe single crystals grown by modified Bridgman method have been studied by using XRD, Raman and I-V measurements. XRD spectra reveal that undoped and boron doped crystals investigated have hexagonal structure with lattice parameters a = 4.005 ?, c = 16.640 ? and z = 4, belonging to the P63/mmc space group. The strongest peak in the XRD patterns is due to the reflection from the (004) plane indicating that these crystals grew with a preferred orientation. Raman spectra show phonon bands in the 400-450 cm-1 wavenumber range characteristics of InSe single crystals. Temperature dependence of conductivity of undoped and boron doped InSe single crystals show three different mechanisms discerned as extended state conductivity, conduction in band tail and conduction in localized sites. It is observed that electrical conductivity increases while activation energy decreases with increasing boron concentration.
关键词： Raman,XRD,activation energy,Boron doped InSe single crystals
更新于2025-09-10 09:29:36