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Highly Sensitive and Selective PbTiO3 Gas Sensors with Negligible Humidity Interference in Ambient Atmosphere
摘要： Three PbTiO3 nanostructures were synthesized using a one-step hydrothermal reaction with different TiO2 powders as Ti sources, and their gas sensing properties were investigated. The sensor comprising PbTiO3 nanoplates exhibited a high response (resistance ratio = 80.4) to 5 ppm ethanol at 300 °C and could detect trace concentrations of ethanol down to 100 ppb. Moreover, the sensor showed high ethanol selectivity and nearly the same sensing characteristics despite the wide range of humidity variation from 20% RH to 80% RH. The mechanism for humidity-independent gas sensing was elucidated using the diffuse reflectance infrared Fourier transform spectra. PbTiO3 nanoplates are new and promising sensing materials that can be used for detecting ethanol in a highly sensitive and selective manner with negligible interference from ambient humidity.
关键词： selectivity,ethanol,PbTiO3 nanoplate,gas sensor,humidity interference
更新于2025-09-23 15:23:52
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Formation of zirconia precursor nanoplates mediated by ionic liquid and transformation to monoclinic ZrO <sub/>2</sub> nanostructures
摘要： The [Zr(OH)5]– imidazolium complex was used to synthesize a zirconia precursor with plate-like nanostructure hydrolyzed under strong acid conditions, which was characterized by means of powder X-ray diffraction, thermogravimetric-differential scanning calorimetry, Fourier transform infrared spectroscopy, Raman spectroscopy, elemental analysis, inductively coupled plasma and electronic differential system. The zirconia precursor can be transformed to monoclinic ZrO2 by annealing at a temperature above 400 °C. With the increasing of the curing temperature, it tended to give rise to porous ZrO2 nanostructures.
关键词： Zirconia precursor,Zirconium oxide,Anion exchange reaction,Nanoplate,Ionic liquid
更新于2025-09-23 15:22:29
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Surface passivation of GaAs (0?0?1) by Hg2Cl2 nanoplates combined with hexadecanethiol
摘要： Surface states in III–V semiconductor materials have detrimental effects on their optical and electronic properties, and the passivation of GaAs surface has become of longstanding interest. Here, we demonstrated a two-step process to greatly reduce surface states of GaAs (0 0 1) by a combination of Hg2Cl2 and alkanethiol. Firstly, uniformly distributed Hg2Cl2 nanoplates with a size around 200 nm were deposited on GaAs surface by the incubation of the etched wafer into the mercury (II) chloride solution, without the need of a reducing agent. Secondly, hexadecanethiol (HDT) molecules were assembled on the Hg2Cl2-GaAs hybrid surface, which decreases the density of surface states through electron transfer processes. Noticeably, after such two steps, a significant enhancement of photoluminescence (PL) signal was noted. It may be due to the fact that components of As2O3 and As0 which are identified as major sources of the surface states are reduced considerably, or even disappear. Chemical state changes of mercury species are expected to play a key role in achieving the surface passivation. Obtained hybrid GaAs materials with considerably improved photonic signals open a new avenue for the fabrication of electronic and optoelectronic devices.
关键词： Surface states,GaAs (0 0 1),Hg2Cl2 nanoplate,PL enhancement,Electrical passivation
更新于2025-09-23 15:22:29
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Impact paint sensor based on polymer/multi-dimension carbon nano isotopes composites
摘要： We presented a novel impact paint sensor made of piezoresistive nano-carbon composites and studied its characteristics. The paint sensors were fabricated with multi-walled carbon nanotube (MWCNT), exfoliated graphite nano-platelets (xGnP), and a hybrid type of the two nano-carbon fillers and were sprayed onto a carbon fiber reinforced plastic (CFRP) panel for lab testing. In ball drop impact test, the MWCNT-xGnP-based hybrid sensor showed the best characteristics in impact energy sensing within the range 0.07-1.0J. We also studied the piezoresistive mechanism due to dimensional variations of nano carbon isotopes for sensor design. Piezorestivity of nano-carbon sensor was significantly dominated the electrical contact variation of the electrical fillers in a matrix. This study is expected to provide a feasibility test for designing impact paint sensors with optimized sensitivity for a composite structural health monitoring (SHM).
关键词： Carbon nanotube (CNT),Exfoliated graphite nanoplate (xGnP),Structural health monitoring (SHM),Unmanned aerial vehicle (UAV),Impact paint sensor
更新于2025-09-23 15:22:29
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Controlled synthesis of SnSxSe2?x nanoplate alloys via synergetic control of reactant activity and surface defect passivation control with surfactant and co-surfactant mixture
摘要： Two-dimensional (2D) metal dichalcogenide nanomaterials have been receiving enormous research interest for electronic, optoelectronic, and catalytic applications. However, the facile tunability of alloying and doping, as well as the successful formation of ideal defect-free nanoplate morphology have been hardly achieved for 2D nanomaterials. Herein, we successfully synthesized a series of 2D solid-solution SnSxSe2(cid:1)x particles of 0.20–2.00 μm width and 30–68 nm thickness with morphological defect-free nanoplate via a solvothermal reaction. With controlled reactivities of elemental chalcogen precursors, a co-surfactant hexylamine together with a structure-directing agent polyvinylpyrrolidone was found to be essential for realizing ideal defect-free nanoplate morphology of SnSxSe2(cid:1)x particles without either cabbage-like or twinned structure. The successful synthesis of morphologically defect-free SnSxSe2(cid:1)x nanoplates with rationally controlled energy band gaps ranging from 1.36 eV for SnSe2 to 1.96 eV for SnS2 could provide promising materials for electronics, optoelectronics, and electrocatalytic applications.
关键词： 2D nanomaterials,Nanoplate,SnSe2,SnS2,Band gap,SnSxSe2(cid:1)x
更新于2025-09-19 17:13:59
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p-GaN/n-ZnO Nanoplate/CsPbBr3 Quantum Dots Heterojunction Light-Emitting Diode for Dual-Wavelength Emission
摘要： In this paper, we report a p-GaN/n-ZnO nanoplate/CsPbBr3 quantum dots (QDs) heterojunction light-emitting diode (LED) for dual-wavelength emission. ZnO nanoplates were prepared by vapor phase transport on the GaN thin film to form the p-GaN/n-ZnO nanoplate heterojunction. Afterwards, green CsPbBr3 QDs (band gap of 2.25 eV) were deposited on ZnO nanoplates to realize green light emission. The structure and photoluminescence of the ZnO nanoplates and CsPbBr3 QDs were characterized. The as-prepared LED device with turn-on voltage of ~ 2.7 V displays a typical rectification behavior. The electroluminescence spectra with narrow emission peaks reveal the device presents commendable dual-wavelength electroluminescence performance at ~ 385 nm and ~ 512 nm and the electroluminescence intensity saturates at about 65 mA/cm2. Moreover, the detailed electroluminescence mechanism including emission originate of n-ZnO/p-GaN heterojunction was discussed based on the band diagram. Thus, our work indicates compelling potential for the practical application of perovskite LEDs.
关键词： CsPbBr3 QDs,Light emitting diode,electroluminescence,ZnO nanoplate
更新于2025-09-16 10:30:52
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WO3/BiVO4 Type-II Heterojunction Arrays Decorated with Oxygen-deficient ZnO Passivation Layer: a Highly Efficient and Stable Photoanode
摘要： In present work, we report a ternary WO3/BiVO4/ZnO photoanode with boosted PEC efficiency and stability towards highly efficient water splitting. The type-II WO3/BiVO4 heterojunction arrays are firstly prepared by hydrothermal growth of WO3 nanoplate arrays onto the substrates of ?uorine-doped tin oxide (FTO) coated glasses, followed by spin-coating of BiVO4 layers onto the WO3 nanoplate surfaces. After that, thin ZnO layers are further introduced onto the WO3/BiVO4 heterojunction arrays via atomic layer deposition (ALD), leading to the construction of ternary WO3/BiVO4/ZnO photoanodes. It is verified that the ZnO thin layer in WO3/BiVO4/ZnO photoanode contains abundant oxygen vacancies, which could be acted as an effective passivation layer to enhance the charge separation and surface water oxidation kinetics of photogenerated carriers. The as-prepared WO3/BiVO4/ZnO photoanode produces a photocurrent of 2.96 mA cm-2 under simulated sunlight with an incident photon-to-current conversion e?ciency (IPCE) of ～72.8 % at 380 nm at a potential of 1.23 V vs. RHE without cocatalysts, both of which are comparable to the state-of-art WO3/BiVO4 counterparts. Moreover, the photocurrent of WO3/BiVO4/ZnO photoanode shows only 9 % decay after 6 h, suggesting its high photoelectrochemical (PEC) stability.
关键词： type-II heterojunction,WO3/BiVO4,nanoplate arrays,photoelectrochemistry,passivation layer
更新于2025-09-04 15:30:14