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A self-powered photodetector based on two-dimensional boron nanosheets
摘要： Owing to their intriguing characteristics, the ongoing pursuit of emerging mono-elemental two-dimensional (2D) nanosheets beyond graphene is an exciting research area for next-generation applications. Herein, we demonstrate that highly crystalline 2D boron (B) nanosheets can be efficiently synthesized by employing a modified liquid phase exfoliation method. Moreover, carrier dynamics has been systematically investigated by using femtosecond time-resolved transient absorption spectroscopy, demonstrating an ultrafast recovery speed during carrier transfer. Based on these results, the optoelectronic performance of the as-synthesized 2D B nanosheets has been investigated by applying them in photoelectrochemical (PEC)-type and field effect transistor (FET)-type photodetectors. The experimental results revealed that the as-fabricated PEC device not only exhibited a favourable self-powered capability, but also a high photoresponsivity of 2.9–91.7 μA W?1 in the UV region. Besides, the FET device also exhibited a tunable photoresponsivity in the range of 174–281.3 μA W?1 under the irradiation of excited light at 405 nm. We strongly believe that the current work shall pave the path for successful utilization of 2D B nanosheets in electronic and optoelectronic devices. Moreover, the proposed method can be utilized to explore other mono-elemental 2D nanomaterials.
关键词： two-dimensional boron nanosheets,optoelectronic devices,carrier dynamics,liquid phase exfoliation,photodetector
更新于2025-09-23 15:19:57
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Ultrathin Hexagonal PbO Nanosheets Induced by Laser Ablation in Water for Chemically Trapping Surface-Enhanced Raman Spectroscopy Chips and Detection of Trace Gaseous H <sub/>2</sub> S
摘要： Lead oxide (PbO) nanosheets are of significance in design of functional devices. However, facile, green and fast fabrication of ultrathin and homogenous PbO nanosheets with chemically clean surface is still desirable. Herein, a simple and chemically clean route is developed for fabricating such nanosheets via laser ablation of a lead target in water for a short time and then ambient ageing. The obtained PbO nanosheets are (002)-oriented with microsize in planar dimension and ca. 15 nm in thickness. They are mostly hexagonal in shape. Experimental observations of the morphological evolution have revealed that the formation of such PbO nanosheets can be attributed to two processes: (i) laser ablation-induced formation of ultrafine Pb and PbO nanoparticles (NPs); (ii) PbO NPs’ aggregation and their oriented connection growth. Importantly, a composite surface enhanced Raman spectroscopy (SERS) chip is designed and fabricated, by covering a PbO nanosheets’ monolayer on a Au NPs’ film. Such composite SERS chip can be used for the fast and trace detection of gaseous H2S, in which the PbO nanosheets can effectively chemically trap H2S molecules, demonstrating a new application of these PbO nanosheets. The response of this chip to H2S can be detected within 10s and the detection limit is below 1 ppb. Also, this PbO nanosheet-based chip is reusable by heating after use. This study not only deepens understanding the NPs-based formation mechanism of nanosheets, but also provides the renewable SERS-chips for the highly efficient detection of trace gaseous H2S.
关键词： Ultrathin hexagonal PbO nanosheets,Chemically trapping-SERS chip,Trace detection of gaseous H2S,Reusable performance,Laser ablation in water
更新于2025-09-23 15:19:57
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Preparation of highly thermally conductive and electrically insulating PI/BNNSs nanocomposites by hot-pressing self-assembled PI/BNNSs microspheres
摘要： Traditional polymer-based thermally conductive composites with randomly distributed fillers always yield an undesired heat removal due to the lack of efficient heat transfer pathways. Thus, realization of rational and ordered distribution of thermally conductive nanofillers in polymer matrix is believed to be significant for obtaining a desirable thermal conductivity. Herein, a series of thermally conductive polyimide/boron nitride nanosheets (PI/BNNSs) composites with a highly ordered BNNSs network have been successfully prepared. For achieving an uniform dispersion and high orientation of BN nanosheets in PI matrix, self-assembled PI/BNNSs complex microspheres were firstly prepared via the van der Waals interaction, and then these complex microspheres were further hot-pressed at the Tg of PI matrix, which rendered the alignment of BNNSs during the deformation of complex microspheres and built an efficient heat transfer pathway. As a consequence, the resultant composites possess a much higher in-plane thermal conductivity up to 4.25 W/mK with 12.4 vol% oriented BNNSs than those of pure PI and random distribution composite (0.85 W/mK for pure PI and 1.3 W/mK for the PI/random BNNSs-12.4). Meanwhile, these nanocomposites present excellent electrically insulating properties, improved dimensional stabilities and good thermal stabilities. This facile method provides a new way to design and fabricate highly thermally conductive PI-based composites for applying in heat dissipation of modern portable and collapsible electronic devices.
关键词： Boron nitride nanosheets,Polyimide,Complex microspheres,Hot-pressing,Filler orientation
更新于2025-09-23 15:19:57
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Highly Sensitive Photoelectrochemical Biosensor Based on Quantum Dots Sensitizing Bi <sub/>2</sub> Te <sub/>3</sub> Nanosheets and DNA-Amplifying Strategies
摘要： In this work, the Bi2Te3 nanosheets treated by N-vinyl-Pyrrolidinone (NVP) showed the highly sufficient and stable photocurrent for being served as novel photoactive material. Accordingly, with CdTe quantum dots (QDs) sensitizing the Bi2Te3 nanosheets, a photoelectrochemical (PEC) biosensor coupling of DNA amplifying strategies was constructed for sensitive miRNA-21 detection. Initially, the Bi2Te3 nanosheets on electrode have conductive surface states with dissipationless electronic property, thus providing a highly stable photocurrent as well as large surface-to-volume ratio. Then, with the participation of target miRNA-21 and auxiliary DNA, the strand displacement amplification (SDA) took place, thereby opening substantial DNA hairpins for triggering next hybridization chain reaction (HCR). Through the HCR, long DNA tails decorated with CdTe QDs could thus be assembled on electrode for enhancing the photocurrent of Bi2Te3 nanosheets. As a result, the proposed PEC biosensor showed a wide detection range from 10 fM to 100 pM with a detection limit (LOD) of 3.3 fM, displaying a promising avenue to construct simply, ultrasensitive and stable analytical techniques and a tremendous potential in bioanalysis and early clinical diagnosis.
关键词： DNA amplifying strategies,Bi2Te3 nanosheets,sensitive detection,CdTe quantum dots,photoelectrochemical biosensor
更新于2025-09-23 15:19:57
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Passively Q-switched Tm:YAlO3 laser based on WS2/MoS2 two-dimensional nanosheets at 2????m
摘要： A comparison of the pulsed laser performances of 2 μm passively Q-switched Tm:YAlO3 (YAP) lasers based on the use of tungsten disul?de (WS2) and molybdenum disul?de (MoS2) two-dimensional (2D) nanosheets as saturable absorbers is reported. The novel nanosheets were prepared by chemical vapor deposition (CVD) technology. The microstructure and optical characteristics of the nanosheets were investigated experimentally. In a continuous-wave (CW) operation, the maximum output power of 2.8 W was obtained at an absorbed pump power of 6.9 W, with a corresponding slope e?ciency of 46.4%. In a passively Q-switched operation at a pump power of 1.45 W, the average output power, pulse width, repetition rate, pulse energy, and peak power for the Tm:YAP/WS2 laser were 0.11 W, 2.65 μs, 34.7 kHz, 2.9 μJ, and 1.23 W, respectively. As for the Tm:YAP/MoS2 laser, the corresponding values were 0.10 W, 2.5 μs, 24.0 kHz, 3.8 μJ, and 1.55 W.
关键词： WS2/MoS2 nanosheets,Passively Q-switched,Chemical vapor deposition,Tm:YAlO3 laser,2 μm
更新于2025-09-23 15:19:57
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A Schottky-junction-based platinum nanoclusters@silicon carbide nanosheet as long-term stable hydrogen sensors
摘要： Hydrogen gas sensors which could be applied in harsh environments (high temperature, corrosion atmosphere, etc.) are highly demanded in special fields such as aerospace and chemical industry. Here, we have successfully produced a platinum nanoclusters@silicon carbide nanosheets (Pt NCs@SiC NSs) gas sensor via a simple one-step wet chemical reduction reaction. The Pt NCs@SiC NSs show good response (15.7%) towards 500 ppm hydrogen under 300 °C. Besides, this device possesses a good linear response towards different hydrogen concentration under 500 ppm and keeps a good stability in one month. The gas sensing properties of Pt NCs@SiC NSs are mainly from the Schottky junction-based structure, in which both reception and transduction process play important roles. This work provides a simple way to prepare high-temperature hydrogen sensors without complex equipment, and the large-scale preparation is also available.
关键词： hydrogen sensing,Pt nanoclusters@SiC nanosheets,chemical reduction reaction,high-temperature
更新于2025-09-23 15:19:57
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Enhancing Electrocatalytic Water Splitting Activities via Photothermal Effect over Bifunctional Nickel/Reduced Graphene Oxide Nanosheets
摘要： Electrocatalytic water splitting has huge potential for generating hydrogen fuel. Its wide application suffers from high energy loss and sluggish reaction kinetics. The adoption of appropriate electrocatalysts is capable of reducing the overpotential and accelerating the reaction. Present research mainly focuses on adjusting electrocatalysts, but the performances are also dependent on other parameters. Therefore, the development of an efficient strategy to enhance electrocatalytic performance through integrating with other driving force, especially a renewable driving force, is of great interest. Herein, we present a photothermal-effect-driven strategy to promote the electrocatalytic hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) activities of nickel/reduced graphene oxide (denoted as Ni/RGO) bifunctional electrocatalysts. The Ni/RGO composite exhibited significant enhancement of activities after exposure to light irradiation (49 mV and 50 mV decrease of overpotential at 10 mA/cm2 for HER and OER, respectively). It was found that the improved electrocatalytic activities arose from the photothermal effect of Ni/RGO, which can efficiently facilitate the thermodynamics and kinetics of electrocatalytic reactions. Furthermore, the photothermal-effect-induced enhancement for electrocatalysis showed good stability, indicating its promising potential in practical application.
关键词： Bifunctional electrocatalysts,Oxygen evolution reaction,Ni/RGO nanosheets,Photothermal effect,Hydrogen evolution reaction
更新于2025-09-19 17:15:36
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DNA-MnO2 Nanosheets as Washing- and Label-Free Platform for Array-Based Differentiation of Cell Types
摘要： Accurate and facile differentiation of cell types is critical for accurate diagnosis and therapy of diseases. However, it remains challenging due to low specificity, requirement of sophisticated instruments, and tedious operation steps. Herein, a simple, washing- and label-free chemical tongue was constructed for differentiation of cell types. In the array-based sensing platform, DNA-ligand ensembles adsorbed on the surface of MnO2 nanosheets were used as sensing probes. Instead of aptamers from cell-SELEX, the randomly designed DNA strands were used, offering versatile interactions with cells. The property that MnO2 nanosheets can be degraded by intracellular glutathione makes the platform avoid the washing step. Eight types of cell lines were distinguished from each other after the data were treated with principal component analysis (PCA). In addition, a 95% of identification accuracy for the randomly selected unknown samples was achieved. The strategy shows an excellent performance not only in distinguishing cell lines but also in the identification of unknown cell samples.
关键词： label-free,pattern recognition,cell types,DNA-MnO2 nanosheets,washing-free
更新于2025-09-19 17:15:36
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Metal-ion bridged high conductive RGO-M-MoS2 (M = Fe3+, Co2+, Ni2+, Cu2+ and Zn2+) composite electrocatalysts for photo-assisted hydrogen evolution
摘要： Efficient photo-electrocatalysts for hydrogen evolution reaction (HER) are synthesized using a facile one-step hydrothermal method. With metal-ion bridges, highly dispersed molybdenum disulfide (MoS2) nanolayers are vertically grown on the reduced graphene oxide (RGO) to form RGO-M-MoS2 photocatalysts for HER, where M = Fe3+, Co2+, Ni2+, Cu2+ and Zn2+. The results show that the cross-bridging ions can modulate the MoS2 growth priority and act as efficient charge transfer channels between RGO and MoS2, and combine the advantages of the high conductivity of graphene with the photo-electrochemical activity of MoS2. The metal-ion bridged MoS2-M-RGO heterostructures demonstrate superior catalytic activity toward hydrogen evolution reaction (HER) in acid medium, evidenced by the remarkable higher catalytic current density at low overpotential compared with that of MoS2-RGO without metal-ion bridge. This study provides a novel and facile route for establishing efficient composite photo-electrocatalysts for water splitting to generate hydrogen.
关键词： hydrogen evolution reaction,MoS2 nanosheets,reduced graphene oxide,metal-ion bridge
更新于2025-09-19 17:15:36
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C-doping into h-BN at low annealing temperature by alkaline earth metal borate for photoredox activity
摘要： BCN (boron carbon nitride) nanosheets are promising photocatalyst materials for solar fuel production by visible light-driven water splitting and CO2 reduction due to their tunable band gap and unique properties. C-doping into h-BN by thermal annealing makes possible the preparation of BCN nanosheets with photocatalytic activity under visible light irradiation, but it generally requires a very high temperature (>1250 °C) from the thermodynamic viewpoint. Here, we report a new method to prepare BCN nanosheets with visible light-photocatalytic activity at lower annealing temperature (1000 °C) than equilibrium by adding alkaline earth metal compounds. BCN nanosheets formed in borate melt show a clear layered structure, tunable bandgap and photocatalytic activity for water splitting and CO2 reduction under visible light illumination. This provides a direction for doping other elements into h-BN at low annealing temperature by alkaline earth metal borates.
关键词： h-BN,low annealing temperature,BCN nanosheets,water splitting,CO2 reduction,C-doping,photoredox activity,alkaline earth metal borate
更新于2025-09-19 17:15:36