- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
pH-Controlled fluorescence switching in water-dispersed polymer brushes grafted to modified boron nitride nanotubes for cellular imaging
摘要： pH-Switchable, fluorescent, hybrid, water-dispersible nanomaterials based on boron nitride nanotubes (BNNTs) and grafted copolymer brushes (poly(acrylic acid-co-fluorescein acrylate) – P(AA-co-FA)) were successfully fabricated in a two-step process. The functionalization of BNNTs was confirmed by spectroscopic, gravimetric and imaging techniques. In contrast to “pure” BNNTs, P(AA-co-FA)-functionalized BNNTs demonstrate intense green fluorescence emission at 520 nm. Under neutral or alkaline pH values, P(AA-co-FA)-functionalized BNNTs are highly emissive in contrast to acidic pH conditions where the fluorescent intensity is absent or low. No increase in the absorption was observed when the suspension pH was increased from 7 to 10. The functionalized BNNTs are easily taken up by human normal prostate epithelium (PNT1A) and human prostate cancer cell lines (DU145) and are suitable for further evaluation in cellular imaging applications.
关键词： pH switching,surface modification,cellular imaging,fluorescence,boron nitride nanotubes,polymer brushes
更新于2025-09-12 10:27:22
-
Synthesis of Perovskite CsPbBr <sub/>3</sub> Quantum Dots/Porous Boron Nitride Nanofiber Composites with Improved Stability and Their Reversible Optical Response to Ammonia
摘要： All-inorganic CsPbX3 (X = Cl, Br, I) perovskite quantum dots (QDs) have great potential for various applications due to their excellent photoluminescence properties. However, poor stability under long-term storage hinders their applications. Herein we report the utilization of porous boron nitride nanofibers (BNNFs) as a promising carrier for anchoring of CsPbBr3 QDs. Due to the good dispersion and immobilization of CsPbBr3 QDs, the resulting CsPbBr3/BNNF composites show excellent photostability and superior long-term storage stability in an air environment. Moreover, the CsPbBr3/BNNF composites exhibit an interesting ammonia-responsive behavior: i.e., a distinct decrease in photoluminescence intensity upon exposure to ammonia gas and the subsequent photoluminescence recovery after post-treatment in nitrogen gas. Even after treatment with ammonia gas for 3 h, the composites can still be recovered under nitrogen gas treatment. The fast response, reversibility, and stability of CsPbBr3/BNNF composites in the presence of ammonia gas could inspire a broader range of applications.
关键词： photostability,reversible optical response,perovskite quantum dots,boron nitride nanofibers,ammonia-responsive behavior
更新于2025-09-12 10:27:22
-
Self-Healing Amorphous Polymers with Room-Temperature Phosphorescence Enabled by Boron-based Dative Bonds
摘要： Dative bonds are crucial for room-temperature phosphorescence (RTP) of metal complexes, which are nevertheless of high cost and toxicity. Here, we develop a class of amorphous RTP polymers based on non-metal dative bonds, through copolymerizing vinylphenylboronic acid and acrylamide derivates. Non-metal dative bonds, formed between boron and nitrogen/oxygen atoms, can populate triplet excitons through charge transfer and immobilize phosphors to suppress nonradiative relaxation, leading to effective RTP lifetime in air. Moreover, the dynamic nature of the dative bonds enables self-healing and anti-counterfeiting abilities of the RTP polymers. The concept of designing non-metal dative bonds can widely expand the horizon and application of RTP polymers.
关键词： self-healing,polymer,dative bond,room-temperature phosphorescence,boron
更新于2025-09-12 10:27:22
-
Oxidising and carburising catalyst conditioning for the controlled growth and transfer of large crystal monolayer hexagonal boron nitride
摘要： Hexagonal boron nitride (h-BN) is well-established as a requisite support, encapsulant and barrier for 2D material technologies, but also recently as an active material for applications ranging from hyperbolic metasurfaces to room temperature single-photon sources. Cost-effective, scalable and high quality growth techniques for h-BN layers are critically required. We utilise widely-available iron foils for the catalytic chemical vapour deposition (CVD) of h-BN and report on the significant role of bulk dissolved species in h-BN CVD, and specifically, the balance between dissolved oxygen and carbon. A simple pre-growth conditioning step of the iron foils enables us to tailor an error-tolerant scalable CVD process to give exceptionally large h-BN monolayer domains. We also develop a facile method for the improved transfer of as-grown h-BN away from the iron surface by means of the controlled humidity oxidation and subsequent rapid etching of a thin interfacial iron oxide; thus, avoiding the impurities from the bulk of the foil. We demonstrate wafer-scale (2”) production and utilise this h-BN as a protective layer for graphene towards integrated (opto-)electronic device fabrication.
关键词： monolayer,hexagonal boron nitride,transfer,2D materials,large crystal,chemical vapor deposition,encapsulation
更新于2025-09-12 10:27:22
-
Hexagonal boron nitride quantum dots as a superior hole extractor for efficient charge separation in WO <sub/>3</sub> based photoelectrochemical water oxidation
摘要： Photoelectrochemical (PEC) water splitting is one of the best desirable technique to harvest clean chemical energy from abundant solar energy. However, the anodic half reaction, i.e. water oxidation is complicated due to the involvement of multiple electrons in this process. Herein, stable WO3 nanoblocks with monoclinic phase have been modified by incorporation of hexagonal boron nitride quantum dots (h-BNQDs) to improve the photogenerated electron-hole separation and additionally to hinder the charge recombination process. The photocurrent density (J) value for modified WO3 photoanode by incorporation of BNQDs has been found to be 1.63 mA/cm2 at the potential of 1.23VRHE which is approximately 2.4 fold higher than the bare WO3 photoanode. The enhancement in photocurrent density is mainly due to the hole extraction property of BNQDs on the surface of the WO3 nanoblocks. A two-fold increment in photogenerated charge carrier density (ND) value has been achieved due to better charge separation of electron-hole pairs in the modified system confirmed by the Mott-Schottky (MS) plot. Present work demonstrates a unique, low-cost strategy for enhancement of PEC water oxidation by modification of photoanode with hole extracting agents.
关键词： charge separation,boron nitride quantum dots,photoelectrochemical water oxidation,hole extracting agent,Tungsten trioxide
更新于2025-09-12 10:27:22
-
Tunable self‐powered n‐SrTiO <sub/>3</sub> photodetectors based on varying CuS‐ZnS nanocomposite film (p‐CuZnS, p‐CuS, and n‐ZnS)
摘要： Dense Boron-doped diamond (BDD) composites were fabricated by high pressure and high-temperature sintering (HPHT) at 5 GPa and 1450 °C for 300 s in presence of Al, B and C as sintering additives. Phase compositions, microstructures, and electrochemical performances of sintered specimens were investigated by X-ray di?raction (XRD), scanning electron microscopy (SEM), and electrochemistry. Results suggested that Al3BC3 and Al4C were formed by in-situ reaction between sintering additives and diamond, which can promote densi?cation of BDD. In addition, BDD composites containing 10 wt% sintering additives exhibited the highest electrical resistivity (4.40 × 10?4 Ω m) and hole concentration (4.55 × 1025/m3). The working potential windows of BDD composite electrodes in 0.1 M H2SO4, 0.1 M Na2SO4 and 0.1 M NaOH electrolytes were estimated to 1.9 V, 2.9 V and 2.3 V, respectively. Electron transfer coe?cients of composite electrodes approached 0.5, con?rming good reversibility. Finally, methylene blue was completely degraded by BDD composite electrodes within 120 min using NaCl as supporting electrolyte.
关键词： High-pressure and high-temperature sintering,Boron-doped diamond,Electrochemical performances
更新于2025-09-11 14:15:04
-
Multi-walled carbon nanotubes /boron oxide composite using plasmonic Ag nanoparticles: Synthesis and SERS characterization
摘要： In this work, by applying a straightforward and easy technique B2O3 doped MWCNTs synthesized using laser ablation in liquid environment (LALE) method. The plasmonc properties of Ag NPs prepared via Lee-Meisel technique was used to prepare high quality substrates for Surface – enhanced Raman scattering (SERS) measurements The size of Ag NPs was acknowledged by UV/Vis/NIR absorption spectroscopy and SEM imaging (< 50 nm). A rather powerful SERS signal was created due to the plasmonic effect and the presence of Ag NPs. Furthermore, SERS spectra were collected in all the synthesized samples. The concentration level down to 10?4 molar (M) of boron oxide (B2O3) doped samples were detected. The recorded data reveals that an enhancement factor (EF) SERS factor of about 105 can be easily achieved applying this method.
关键词： SERS,Ag NPs,Boron oxide,MWCNT
更新于2025-09-11 14:15:04
-
European Microscopy Congress 2016: Proceedings || Si:B doping measurement by dark-field electron holography
摘要： In modern MOS devices, sources and drains are of nanometric dimensions and highly doped (dopant concentration typically > 1020 at.cm-3). Measuring such dopant concentrations and visualizing their spatial extensions in silicon, although mandatory for the development of the technology, is elusive in practice. Several TEM techniques such as EELS and EDX seem suitable to map dopant concentrations with the required resolution but while they are accurate to measure impurities concentrations, they cannot assess whether these impurities are on interstitial or substitutional sites, what is essential to define doping levels. Moreover, the detection of boron suffers from other physical limitations. Finally, bright-field electron holography has been reported to be suited for such measurements but transforming the electrostatic fields which are measured into doping concentrations is far from straightforward. In this work, we have explored the possibility to extract boron concentrations from the measurement of changes of the silicon lattice parameter induced by the substitution of boron atoms. For this we use dark-field electron holography (DFEH) on specifically designed samples. In a first part, we will present the DFEH principle [1]. This is an interferometry technique able to map strain with a precision of the order of 10-4 and a few nanometers spatial resolution over micrometer fields of view. Two diffracted beams, one passing through an unstrained region of the lattice and acting as a reference, the other one passing through the region where strain has to be measured, are forced to interfere by using an electrostatic biprism and thus create an interference pattern (see figure 1). A phase map is extracted from the pattern by Fourier transform and converted into an atomic displacement field. By using two non-collinear diffraction vectors, all the components of the strain tensor in the observation plane can be obtained. For our experiment, a sample consisting of five 50 nm-thick doped layers of increasing boron concentrations ranging from 3E18 at.cm-3 to 8.5E19 at.cm-3 was grown by RP-CVD, under conditions insuring both extremely low concentrations of impurities and the full activation of boron [2]. The sample was further checked by SIMS and ECVP measurements, demonstrating that 100 % of boron atoms are on substitutional sites in all the doped layers. DFEH was used to measure the deformation of the doped layers. We could thus deduce the silicon lattice expansion coefficient (β) resulting from the adding of boron atoms in the crystalline silicon network, from these measurements, as explained below. The boron atoms being on substitutional sites, the Si:B doped layers can be seen as solid solutions as confirmed by the homogeneity of the deformations imaged by DFEH. These layers are pseudomorphic on the pure silicon lattice as confirmed by the mapping of the in-plane strain by DFEH. Thus, the change of the lattice parameter resulting from the incorporation of boron atoms is solely supported by the out-of-plane strain, through the Poisson’s reaction of the material (figure 2). From the modeling of this sample by FEM and taking into account the relaxation affecting the thin lamella used for DFEH, we are able to retrieve the values of the relaxed Si:B lattice parameter as a function of the substitutional boron concentration. As expected for a solid solution, we find a linear relation between these two parameters. Knowing the boron concentration and the Si:B lattice parameter profiles, we are able to deduce that β coefficient equals -6.5E-24 cm3 (figure 3). Figure 4 compares the results we have obtained with those found in the literature, often measured by XRD. Finally, β, the coefficient relating the boron concentration to the lattice parameter, allows us to transform a strain map obtained by DFEH into a “substitutional boron concentration” map with a precision of 3E19 at.cm-3 and a spatial resolution of 5 nm. We will illustrate the DFEH effectiveness to measure and image dopant concentrations in “real samples” through few examples, and will discuss the complementarity of the information obtained by this method and by bright-field electron holography.
关键词： doping,DFEH,silicon,boron,strain
更新于2025-09-11 14:15:04
-
Effects of Hexagonal Boron Nitride Sheets on the Optothermal Performances of Quantum Dots-Converted White LEDs
摘要： Recently, quantum dots-converted white light-emitting diodes (QDs-WLEDs) are attracting numerous attention due to their high luminous efficiency and excellent color quality. As for color conversion material, the quantum dots (QDs) are commonly embedded into a low-thermal-conductivity polymer matrix. In this case, their generated heat during the photoluminescence process can hardly be dissipated into the heat sink, leading to a high working temperature and reduced lifetime. Adding particles with high thermal conductivity to the QDs layer can enhance its thermal conductivity, and thus reduce QDs’ working temperature. At the same time, these particles may affect the optical properties of QDs. However, this problem has still not been deeply studied. In this article, we systematically investigated the effects of the highly thermal-conductive hexagonal boron nitride sheets (hBNSs) on the optothermal performances of QDs/phosphor film in white light-emitting diodes (WLEDs). The thermal conductivity of QDs/phosphor film was significantly increased by 24% after adding 5wt% of 45-μm-diameter hBNS. As for the optical performance, the transparency of the silicone gel film with 45-μm-diameter hBNS was much better than that with 6–9-μm-diameter hBNS under the same weight fraction. Furthermore, the scattering effect of hBNS plays a more important role in enhancing the light conversion performance of QDs than that of phosphor. At last, a color stability test showed the increasing rate of correlated color temperature (IRCCT) of hBNS-added WLEDs are 21% smaller than that of common WLEDs after working 153 h, meaning a better QDs stability in hBNS-added WLEDs.
关键词： light conversion,quantum dots (QDs),Hexagonal boron nitride sheets (hBNSs),thermal conductivity
更新于2025-09-11 14:15:04
-
Small Band gap Boron Dipyrromethene-Based Conjugated Polymers for All-Polymer Solar Cells: The Effect of Methyl Units
摘要： Naphthalene diimide (NDI)-based conjugated polymers have been widely used as the nonfullerene electron acceptor for all-polymer solar cells (all-PSCs), but their low absorption coefficient in the near-infrared (NIR) region severely limits the light harvesting ability in solar cells and hence lowers their photovoltaic performance. In this work, two narrow band gap donor?acceptor conjugated polymers based on boron dipyrromethene (BODIPY) as the electron-deficient unit were developed as the electron donor to combine with a NDI-polymer acceptor in order to significantly improve the photoresponse in the NIR region. More importantly, we found that methyl substitution on the BODIPY segment played an important role in charge transport in these polymers. When methyl units were attached to the α-position of BODIPY, the polymer PMBBDT exhibited high-lying energy levels, improved crystallinity, and dramatically high hole mobility compared to the polymer PBBDT without methyl substitution. Consequently, the power conversion efficiencies (PCEs) could be enhanced from 0.32% for PBBDT- to 5.8% for PMBBDT-based all-PSCs, and the photoresponse covered from 300 to 900 nm. Our results demonstrate that methyl-substituted BODIPY-based conjugated polymers are promising candidates to solve the NIR absorption issue in NDI polymers and, therefore, can be potentially used to further boost the PCEs of all-PSCs similar with organic solar cells based on NIR-fused ring electron acceptors.
关键词： Boron dipyrromethene,Methyl substitution,Conjugated polymers,Near-infrared absorption,All-polymer solar cells
更新于2025-09-11 14:15:04