- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Light-Assisted Room-Temperature NO2 Sensors Based on Black Sheet-Like NiO
摘要： In this study, we use two-dimensional black flake nickel oxide as the sensitive material which was synthesized by a facile hydrothermal route. The as-synthesized sheet-like NiO possessed a large specific surface area, as verified by BET characterization. The as-prepared NiO nanosheets had strong absorption in the range of 250–800 nm including UV and visible light. Upon exposure to ppb-level NO2, the presented sensors showed significant responses under light illumination at room temperature. In addition, the light wavelength also had a remarkable effect on the sensing performance in terms of sensitivity, response and recovery kinetics. Furthermore, the sensor showed a low humidity dependence.
关键词： NiO,light illumination,room temperature,NO2
更新于2025-09-09 09:28:46
-
Visible-Light Photocatalyzed Deoxygenation of N-Heterocyclic <i>N</i> -Oxides
摘要： A scalable and operationally simple method is described that allows for the chemoselective deoxygenation of a wide range of N-heterocyclic N-oxides (a total of 36 examples). This visible-light-induced protocol features the use of only commercially available reagents, room-temperature conditions, and unprecedented chemoselective removal of the oxygen atom in a quinoline N-oxide in the presence of a pyridine N-oxide in the same molecule through the judicious selection of a photocatalyst.
关键词： chemoselective,deoxygenation,room-temperature,N-heterocyclic N-oxides,visible-light photocatalysis
更新于2025-09-09 09:28:46
-
Near-Room-Temperature Ethanol Gas Sensor Based on Mesoporous Ag/Zn-LaFeO <sub/>3</sub> Nanocomposite
摘要： The rational design of heterojunction between different metal oxides with mesoporous structures has attracted tremendous attention due to their special physicochemical properties and vital importance for practical applications. In this paper, mesoporous Ag/Zn–LaFeO3 nanocomposite is successfully synthesized through a facile nanocasting technique using KIT-6 as a hard template in sol–gel route and used as sensing materials to achieve an exceptionally sensitive and selective detection of trace ppm-level ethanol. The obtained composite possesses high surface area and exhibits excellent sensing response (64.2 for 100 ppm) to ethanol at near-room with relatively fast response/recovery time. When tested with the concentrations as low as 5 ppm, it also shows a remarkably high selectivity to the ethanol, but only minor responses to other interfering gases. These enhanced gas-sensing properties are attributed to the combination of mesoporous nanostructure and Ag/Zn–LaFeO3 heterogeneous composites.
关键词： mesoporous,ethanol,gas sensors,near-room temperature,Ag/Zn–LaFeO3 nanocomposite
更新于2025-09-09 09:28:46
-
Visible light enhanced black NiO sensors for ppb-level NO2 detection at room temperature
摘要： Although extensive studies have been carried out on n-type semiconductors for room-temperature gas sensor applications, some intrinsic problems remain. Therefore, other interesting attempts should be adopted to solve these issues, like p-type semiconductors. Previous studies have demonstrated that p-type semiconductor gas sensors exhibit better selectivity and less humidity dependence due to the distinctive oxygen adsorption and surface reactivity. Visible light is used as the external activation source to accelerate the sensing kinetics instead of heating. Stoichiometric NiO cannot absorb visible lights. Inspired by the works of black TiO2, we adopted three methods to prepare black NiO. XPS characterizations reveal that the presence of Ni3+ ions leads to the formation of black NiO. However, not all black NiO samples show good responses to NO2 at room temperature. Three main routes: synthesizing specific morphology with large specific surface area and porosity, introduction of Ni3+ ions and oxygen vacancies, are needed to get the enhanced sensing performance. The black NiO samples with large specific surface area and oxygen vacancies and Ni3+ ions show obvious response towards ppb-level NO2 with visible light irradiation at room temperature. Furthermore, light wavelength is found to play a vital role in the sensing characteristics, and blue light is the optimal choice. Different from traditional NiO sensors operated at high temperatures exhibiting superior response to reducing gases, the black NiO show excellent selectivity towards oxidizing gas, ppb-level NO2, at room temperature illuminated by blue light. In contrast with n-type semiconductors, the black NiO samples also exhibit less humidity dependence.
关键词： Room temperature,NO2 sensor,NiO,Visible light irradiation
更新于2025-09-09 09:28:46
-
Long-lived non-classical correlations towards quantum communication at room temperature
摘要： Heralded single-photon sources with on-demand readout are a key enabling technology for distributed photonic networks. Such sources have been demonstrated in both cryogenic solid-state and cold-atoms systems. Practical long-distance quantum communication may benefit from using technologically simple systems such as room-temperature atomic vapours. However, atomic motion has so far limited the single-excitation lifetime in such systems to the microsecond range. Here we demonstrate efficient heralding and readout of single collective excitations created in warm caesium vapour. Using the principle of motional averaging we achieve a collective excitation lifetime of 0.27 ± 0.04 ms, two orders of magnitude larger than previously achieved for single excitations in room-temperature sources. We experimentally verify non-classicality of the light-matter correlations by observing a violation of the Cauchy-Schwarz inequality with R = 1.4 ± 0.1 > 1. Through spectral and temporal analysis we investigate the readout noise that limits single-photon operation of the source.
关键词： quantum communication,room-temperature atomic vapours,motional averaging,non-classical correlations,single-photon sources
更新于2025-09-09 09:28:46
-
Sulfur doping of M/In <sub/>2</sub> O <sub/>3</sub> (M=Al,W) nanowires with room temperature near infra red emission
摘要： We have investigated the growth of Al doped In2O3 nanowires via the vapor-liquid-solid mechanism at 800?C using Au as a catalyst. We find that the Al is not incorporated into the cubic bixbyite crystal structure of In2O3 but nevertheless was detected in the form of Al2O3. The nanowires had metallic like conductivities and exhibited photoluminescence at 2.3 eV which shifted to 1.5 eV after exposure to H2S above 500?C due to the formation of β-In2S3 and deep donor to acceptor transitions with a lifetime of ≈ 1 μs. The near infra red emission was also observed in W/In2O3 but not in W/SnO2 core-shell nanowires after processing under H2S at 600?C, confirming it is related to β-In2S3. The nanowires remain one dimensional up to 900?C due to the shell which is interesting for the fabrication of high temperature nanowire sensors.
关键词： β-In2S3,M/In2O3 nanowires,Al doped In2O3,room temperature near infra red emission,Sulfur doping
更新于2025-09-09 09:28:46
-
Intrinsic and Extrinsic Heavy Atom Effect on the Multifaceted Emissive Behavior of Cyclic Triimidazole
摘要： Since heavy halogen atoms can be used to tune the emissive properties of organic luminogens, the understanding of their role in the photophysics is fundamental for materials engineering. Here, the extrinsic and intrinsic heavy atom effects on the photophysics of organic crystals are separately evaluated by comparing cyclic triimidazole (TT) with its mono-iodo derivative (TTI) and its cocrystal with diiodotetrafluorobenzene (TTCo). Crystals of TT show room temperature ultralong phosphorescence (RTUP) originated from H-aggregation. TTI and TTCo display two additional long lived components whose origin is elucidated through single crystal X-ray and DFT-TDDFT studies. The results highlight the different effects of the I atom on the three phosphorescent emissions. Intrinsic heavy atom effects play a major role on molecular phosphorescence which is displayed at RT only for TTI. H-aggregate RTUP and the I···N XB induced phosphorescences on the other side depend only on packing features.
关键词： photophysics,co-crystal,room temperature phosphorescence,halogen bonding,time resolved spectroscopy
更新于2025-09-04 15:30:14
-
Efficient and Long-lived Room Temperature Organic Phosphorescence: Theoretical Descriptors for Molecular Designs
摘要： Room-temperature phosphorescence (RTP) with long afterglow from pure organic materials has attracted great attentions for their potential applications in biological imaging, digital encryption and optoelectronic device and so on. Organic materials have been long considered to be non-phosphorescence owing to the weak molecular spin-orbit coupling and highly sensitive to temperature. However, recently, some purely organic compounds can demonstrate highly efficient RTP with long afterglow upon aggregation while others fail. Namely, it remains a challenge to expound the underline mechanisms. In this study, we present the molecular descriptors to character the phosphorescence efficiency and lifetime. For prototypical RTP system consists of carbonyl group and π-conjugated segments, the excited states can be regarded as admixture of n→π* (with portion α) and π→π* (portion β). Starting from phosphorescent process and El-Sayed rule, we deduced that (i) the intersystem crossing (ISC) rate of S1→Tn is mostly governed by the modification of the product of α and β, and (ii) the ISC rate of T1→S0 is determined by the β value of T1. Thus, the descriptors (γ=α×β, β) can be employed to describe the RTP character of organic molecules. From hybrid quantum mechanics and molecular mechanics (QM/MM) calculations, we illustrated the relationships amongst the descriptors (γ, β), phosphorescent efficiency and lifetime, as well as spin-orbit coupling constants. We stressed that the large γ and β values are favorable to the strong and long-lived RTP in organic materials. Experiments have reported confirmations of these molecular design rules.
关键词： Organic materials,Molecular descriptors,Room-temperature phosphorescence,QM/MM calculations,Spin-orbit coupling
更新于2025-09-04 15:30:14
-
High magnetoelectric coupling in Si-integrated AlN/NiMnIn thin film double layers at room temperature
摘要： The current study explores the presence of strong magnetoelectric (ME) coupling in a sputtered deposited NiMnIn/aluminum nitride (AlN) heterostructure on an Si substrate. The X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy results confirm the formation of a pure AlN wurtzite phase in the ME heterostructure. The magnetization vs temperature measurement shows the presence of the martensite transformation region of the NiMnIn/AlN heterostructure. The magnetic measurements exhibit the room temperature ferromagnetic nature of the NiMnIn/AlN heterostructure. The NiMnIn/AlN ME heterostructure was found to have a high ME coupling coefficient of (cid:2)99.2 V/cm Oe at Hdc ? 300 Oe. The induced ME coupling coefficient shows a linear dependency on Hac up to 8 Oe.
关键词： room temperature,Si-integrated,thin film,magnetoelectric coupling,AlN/NiMnIn
更新于2025-09-04 15:30:14