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Room-temperature quantum interference in single perovskite quantum dot junctions
摘要： The studies of quantum interference effects through bulk perovskite materials at the ?ngstrom scale still remain as a major challenge. Herein, we provide the observation of room-temperature quantum interference effects in metal halide perovskite quantum dots (QDs) using the mechanically controllable break junction technique. Single-QD conductance measurements reveal that there are multiple conductance peaks for the CH3NH3PbBr3 and CH3NH3PbBr2.15Cl0.85 QDs, whose displacement distributions match the lattice constant of QDs, suggesting that the gold electrodes slide through different lattice sites of the QD via Au-halogen coupling. We also observe a distinct conductance ‘jump’ at the end of the sliding process, which is further evidence that quantum interference effects dominate charge transport in these single-QD junctions. This conductance ‘jump’ is also confirmed by our theoretical calculations utilizing density functional theory combined with quantum transport theory. Our measurements and theory create a pathway to exploit quantum interference effects in quantum-controlled perovskite materials.
关键词： charge transport,quantum interference,room-temperature,mechanically controllable break junction,perovskite quantum dots
更新于2025-09-11 14:15:04
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Preparation of hexagonal micro-sized α-Al2O3 platelets from a milled Al(OH)3 precursor with NH4F and NH4Cl additives
摘要： In the present work, an Ni5P4/Ni porous composite with a Ni foam as the skeleton was prepared through phosphorization calcination at 500 1C. Meanwhile, the catalytic activity of the as-prepared Ni5P4/Ni porous composite was explored for the treatment of a large-volume e?uent with a high concentration of 4-nitrophenol at room temperature. At last, the catalytic mechanism was discussed preliminarily. The results indicated that the Ni5P4/Ni porous composite possessed remarkable catalytic activity for the borohydride-assisted reduction of 4-nitrophenol. When the concentration of 4-nitrophenol was 1.0 (cid:2) 10(cid:3)3 mol L(cid:3)1, the catalytic reduction e?ciency of 4-nitrophenol was up to 99% within 13 min over the aforementioned sample. More interestingly, it was suitable for the treatment of a large-volume e?uent with a high concentration of 4-nitrophenol. Almost 99% of 4-nitrophenol (1.0 (cid:2) 10(cid:3)2 mol L(cid:3)1, 100 mL) could be removed within 30 min. Even when 4-nitrophenol was near saturation in water (5.0 (cid:2) 10(cid:3)2 mol L(cid:3)1), 4-nitrophenol could still be removed absolutely from water after a 165 min reaction in the presence of the Ni5P4/Ni porous composite. In the catalytic process, Ni5P4 could serve as the active sites and accelerate the formation of hydrogen atoms from BH4(cid:3). Meanwhile, the Ni skeleton could make the electron transfer faster in the catalytic system. Besides, the macroporous structure of the sample also played an important role in the catalysis process.
关键词： room temperature,large-volume effluent,4-nitrophenol,catalytic reduction,Ni5P4/Ni porous composite
更新于2025-09-11 14:15:04
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Room temperature operation of InAsSb quantum dashes laser near 1.8 μm based on InP (001) substrate
摘要： Single-stack InAsSb self-assembled quantum dashes (QDashes) laser grown by metalorganic vapor phase epitaxy based on InP (001) substrate is reported. High-quality InAsSb quantum dashes have been acquired under the optimized growth conditions, such as substrate temperature, growth rate, deposition thickness and V/III ratio. Surface QDashes morphologies have been characterized by atomic force microscopy whereas the ones buried in active region have been investigated by transmission electron microscope with high resolution X-ray Energy Dispersive Spectroscopy to confirm the antimony composition. Double channel waveguide laser with 40 μm width ridge has been fabricated by standard optical lithography and wet etching. Pulsed room temperature operation demonstrates the wavelength from 1.72 to 1.79 μm for different injection currents. In addition, the laser peak output power can exceed 600 mW with 12.8% of differential quantum efficiency and even under continuous wave operation, the maximum optical power still remains 26 mW.
关键词： room temperature operation,InAsSb,laser,quantum dashes,InP substrate
更新于2025-09-11 14:15:04
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Superior properties in room-temperature colloidal-dot quantum emitters revealed by ultralow-dark-count detections of temporally-purified single photons
摘要： The realization of high-quality quantum emitters that can operate at room temperature is important for accelerating the application of quantum technologies, such as quantum communication, quantum information processing, and quantum metrology. In this work, we study the photon-antibunching properties on room-temperature emission from individual colloidal quantum dots (CQDs) using superconducting-nanowire single-photon detectors and temporal filtering of the photoluminescence decay curve. We find that high single-photon purities and high photon-generation rates can be simultaneously achieved by removing the signals originating from the sequential two-photon emission of biexcitons created by multiple excitation pulses. We successfully demonstrate that the ultrahigh performance of the room-temperature single-photon sources showing g(2)(0) ? 10?2 can be confirmed by the ultralow-dark-count detection of the temporally purified single photons. These findings provide strong evidence for the attractiveness of CQDs as candidates for high-quality room-temperature quantum light sources.
关键词： single-photon sources,room-temperature,superconducting-nanowire single-photon detectors,quantum emitters,colloidal quantum dots,temporal filtering
更新于2025-09-11 14:15:04
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Transparent Collision Visualization of Point Clouds Acquired by Laser Scanning
摘要： Exploring two-dimensional (2D) materials with room-temperature ferromagnetism and large perpendicular magnetic anisotropy is highly desirable but challenging. Here, through first-principles calculations, we propose a viable strategy to achieve such materials based on transition metal (TM) embedded borophene nanosheets. Due to electron deficiency, the commonly existent hexagon boron vacancies in various borophene phases serve as intrinsic anchor points for electron-rich transition metals, which not only adsorb strongly upon the vacancies but also favor to be embedded into the vacancies, forming 2D planar hybrid nanosheets. The adsorption-to-embedding transition is feasible thermodynamically and kinetically, owing to its exothermic nature and relatively small kinetic barriers. After embedding, phase transition is further proposed to obtain diverse structures of TM embedded borophenes with versatile magnetic properties. Based on the example of χ3 phase borophene, several ferromagnetic TM embedded borophene nanosheets with high Curie temperature and large perpendicular magnetic anisotropy have been predicted.
关键词： transition metal embedded borophene nanosheets,first-principles calculations,perpendicular magnetic anisotropy,room-temperature ferromagnetism,two-dimensional materials
更新于2025-09-11 14:15:04
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Tailoring solvent coordination for high-speed, room-temperature blading of perovskite photovoltaic films
摘要： The efficiencies of small-pixel perovskite photovoltaics have increased to above 24%, while most reported fabrication methods cannot be transferred to scalable manufacturing process. Here, we report a method of fast blading large-area perovskite films at an unprecedented speed of 99 mm/s under ambient conditions by tailoring solvent coordination capability. Combing volatile noncoordinating solvents to Pb coordinating solvents achieves both fast drying and large perovskite grains at room temperature. The reproducible fabrication yields a certified module efficiency of 16.4%, with an aperture area of 63.7 cm2. This method can be applied for various perovskite compositions. The perovskite modules also show a small temperature coefficient of ?0.13%/°C and nearly fully recoverable efficiency after 58 cycles of shading, much better than commercial silicon and thin-film solar modules.
关键词： solvent coordination,room-temperature blading,scalable manufacturing,perovskite photovoltaics,module efficiency
更新于2025-09-11 14:15:04
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Highly Plasmonic Titanium Nitride by Room-Temperature Sputtering
摘要： Titanium nitride (TiN) has recently emerged as an attractive alternative material for plasmonics. However, the typical high-temperature deposition of plasmonic TiN using either sputtering or atomic layer deposition has greatly limited its potential applications and prevented its integration into existing CMOS device architectures. Here, we demonstrate highly plasmonic TiN thin films and nanostructures by a room-temperature, low-power, and bias-free reactive sputtering process. We investigate the optical properties of the TiN films and their dependence on the sputtering conditions and substrate materials. We find that our TiN possesses one of the largest negative values of the real part of the dielectric function as compared to all other plasmonic TiN films reported to date. Two-dimensional periodic arrays of TiN nanodisks are then fabricated, from which we validate that strong plasmonic resonances are supported. Our room-temperature deposition process can allow for fabricating complex plasmonic TiN nanostructures and be integrated into the fabrication of existing CMOS-based photonic devices to enhance their performance and functionalities.
关键词： room-temperature sputtering,optical properties,nanostructures,Titanium nitride,plasmonics
更新于2025-09-11 14:15:04
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Water-Based Indium Tin Oxide Nanoparticle Ink for Printed Toluene Vapours Sensor Operating at Room Temperature
摘要： This study is focused on the development of water-based ITO nanoparticle dispersions and ink-jet fabrication methodology of an indium tin oxide (ITO) sensor for room temperature operations. Dimensionless correlations of material-tool-process variables were used to map the printing process and several interpretational frameworks were re-examined. A reduction of the problem to the Newtonian fluid approach was applied for the sake of simplicity. The ink properties as well as the properties of the deposited layers were tested for various nanoparticles loading. High-quality films were prepared and annealed at different temperatures. The best performing material composition, process parameters and post-print treatment conditions were used for preparing the testing sensor devices. Printed specimens were exposed to toluene vapours at room temperature. Good sensitivity, fast responses and recoveries were observed in ambient air although the n-type response mechanism to toluene is influenced by moisture in air and baseline drift was observed. Sensing response inversion was observed in an oxygen and moisture-free N2 atmosphere which is explained by the charge-transfer mechanism between the adsorbent and adsorbate molecules. The sensitivity of the device was slightly better and the response was stable showing no drifts in the protective atmosphere.
关键词： Indium tin oxide,room temperature,inkjet ink,gas sensor,dimensionless number,material printing,nanoparticle
更新于2025-09-10 09:29:36
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Design principle of all-inorganic halide perovskite-related nanocrystals
摘要： All-inorganic halide perovskite (AIHP)-related (e.g., CsPbBr3, Cs4PbBr6, and CsPb2Br5) nanocrystals have attracted great research interest in the recent three years, owing to their unique optical properties. However, rational structural and compositional control of these nanocrystals is still challenging, particularly using the room temperature saturated recrystallization (RTSR) method. Here, we revealed that the structure and the composition of the nanocrystals fabricated by the RTSR approach are highly dependent not only on the previously thought concentration ratio of PbBr2 and CsBr in N-dimethylformamide (DMF), but the previously neglected absolute concentration and reaction time. This is the reason why pure AIHP-related nanocrystals are usually difficult to prepare using the RTSR method. Through a series of carefully designed experiments, we obtained the evolution trend of the precipitation rate of PbBr2 and CsBr within a wide concentration range in DMF. Based on the understanding of the growth mechanism, we achieved preparation of pure or a mixture of CsPbBr3, Cs4PbBr6, and CsPb2Br5 nanocrystals through either control of the concentration of PbBr2 and CsBr or the reaction time. This study deepens our understanding of the growth mechanism of AIHP-related nanocrystals, paving the way for future engineering of nanocrystals with desired structures and compositions. These structures with desired compositions will definitely have promising applications in optical and optoelectronic devices.
关键词： nanocrystals,All-inorganic halide perovskite,room temperature saturated recrystallization,optical properties,optoelectronic devices
更新于2025-09-10 09:29:36
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UV-light-activated H2S gas sensing by a TiO2 nanoparticulate thin film at room temperature
摘要： A UV-light-activated TiO2 thin film gas sensor composed of nanoparticles is reported for H2S detection at room temperature. TiO2 nanoparticulate thin films were fabricated by bar coating of a mixture of TiO2 powder and acetic acid. The morphology and structural properties of the films were examined by scanning electron microscopy, X-ray diffraction, photoluminescence spectroscopy, and absorption spectroscopy. The nil response to H2S was significantly enhanced by UV light irradiation in the response levels and response/recovery kinetics. The effect of the sensor conductance and light intensity towards sensor optimization was discussed. The sensor exhibited high gas selectivity, repeatability, and linearity for practical applications of the sensor, but the interference of humidity on the sensing process needs to be solved. The results exhibited a simple way to detect parts per million concentrations of H2S at room temperature.
关键词： TiO2 nanoparticulate thin film,room temperature sensing,UV-light-activated sensing,H2S
更新于2025-09-10 09:29:36