| 1. |
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| 2. |
- Xu, Haoyuan, et al.
(författare)
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Effect of rare earth doping on electronic and gas-sensing properties of SnO2 nanostructures
- 2022
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Ingår i: Journal of Alloys and Compounds. - : Elsevier. - 0925-8388 .- 1873-4669. ; 909
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Tidskriftsartikel (refereegranskat)abstract
- Tin dioxide (SnO2) and rare earth (Y, La, Pr, Tb, and Er)-doped SnO2 materials were synthesized by a solvothermal method and used for gas sensors. The effect of rare-earth (RE) doping on structural, electronic, and gas-sensing properties of SnO2 has been investigated. According to a comparative study on the gassensing properties of SnO2 and RE-doped SnO2 gas sensors to various testing gases, the RE-doped SnO2 sensors showed enhanced sensitivities to different testing gases. Especially, the Pr-doped SnO2 sensor exhibited outstanding sensing properties to SO2, including a high response of 19.5-50 ppm SO2, excellent selectivity, repaid response and recovery rates, and superior long-term stability. According to the structural analyses, DFT calculation, and the electrochemical measurement of the SnO2 and Pr-SnO2 materials, the improved electron excitation efficiency endowed the Pr-SnO2 with a high density of free electrons that can be trapped by atmospheric oxygen species and participated in SO2-sensing reactions. Moreover, after the Pr doping of SnO2, the enhanced charge carrier transport properties, including prolonged electron lifetime, improved electron diffusion coefficient, and increased effective diffusion length, were conducive to improving the SO2-sensing property.
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| 3. |
- Xu, Haoyuan, et al.
(författare)
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Highly Efficient SO2 Sensing by Light-Assisted Ag/PANI/SnO2 at Room Temperature and the Sensing Mechanism
- 2021
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Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 13:41, s. 49194-49205
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Tidskriftsartikel (refereegranskat)abstract
- Sulfur dioxide (SO2) is one of the most hazardous and common environmental pollutants. However, the development of room-temperature SO2 sensors is seriously lagging behind that of other toxic gas sensors due to their poor recovery properties. In this study, a light-assisted SO2 gas sensor based on polyaniline (PANI) and Ag nanoparticle-comodified tin dioxide nanostructures (Ag/PANI/SnO2) was developed and exhibited remarkable SO2 sensitivity and excellent recovery properties. The response of the Ag/PANI/SnO2 sensor (20.1) to 50 ppm SO2 under 365 nm ultraviolet (UV) light illumination at 20 °C was almost 10 times higher than that of the pure SnO2 sensor. Significantly, the UV-assisted Ag/PANI/SnO2 sensor had a rapid response time (110 s) and recovery time (100 s) to 50 ppm SO2, but in the absence of light, the sensors exhibited poor recovery performance or were even severely and irreversibly deactivated by SO2. The UV-assisted Ag/PANI/SnO2 sensor also exhibited excellent selectivity, superior reproducibility, and satisfactory long-term stability at room temperature. The increased charge carrier density, improved charge-transfer capability, and the higher active surface of the Ag/PANI/SnO2 sensor were revealed by electrochemical measurements and endowed with high SO2 sensitivity. Moreover, the light-induced formation of hot electrons in a high-energy state in Ag/PANI/SnO2 significantly facilitated the recovery of SO2 by the gas sensor.
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| 4. |
- Assalauova, Dameli, et al.
(författare)
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An advanced workflow for single-particle imaging with the limited data at an X-ray free-electron laser
- 2020
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Ingår i: IUCrJ. - 2052-2525. ; 7, s. 1102-1113
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Tidskriftsartikel (refereegranskat)abstract
- An improved analysis for single-particle imaging (SPI) experiments, using the limited data, is presented here. Results are based on a study of bacteriophage PR772 performed at the Atomic, Molecular and Optical Science instrument at the Linac Coherent Light Source as part of the SPI initiative. Existing methods were modified to cope with the shortcomings of the experimental data: inaccessibility of information from half of the detector and a small fraction of single hits. The general SPI analysis workflow was upgraded with the expectation-maximization based classification of diffraction patterns and mode decomposition on the final virus-structure determination step. The presented processing pipeline allowed us to determine the 3D structure of bacteriophage PR772 without symmetry constraints with a spatial resolution of 6.9 nm. The obtained resolution was limited by the scattering intensity during the experiment and the relatively small number of single hits.
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| 5. |
- Li, Haoyuan, et al.
(författare)
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Diffraction data from aerosolized Coliphage PR772 virus particles imaged with the Linac Coherent Light Source
- 2020
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Ingår i: Scientific Data. - : NATURE RESEARCH. - 2052-4463. ; 7:1
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Tidskriftsartikel (refereegranskat)abstract
- Single Particle Imaging (SPI) with intense coherent X-ray pulses from X-ray free-electron lasers (XFELs) has the potential to produce molecular structures without the need for crystallization or freezing. Here we present a dataset of 285,944 diffraction patterns from aerosolized Coliphage PR772 virus particles injected into the femtosecond X-ray pulses of the Linac Coherent Light Source (LCLS). Additional exposures with background information are also deposited. The diffraction data were collected at the Atomic, Molecular and Optical Science Instrument (AMO) of the LCLS in 4 experimental beam times during a period of four years. The photon energy was either 1.2 or 1.7keV and the pulse energy was between 2 and 4 mJ in a focal spot of about 1.3 mu m x 1.7 mu m full width at half maximum (FWHM). The X-ray laser pulses captured the particles in random orientations. The data offer insight into aerosolised virus particles in the gas phase, contain information relevant to improving experimental parameters, and provide a basis for developing algorithms for image analysis and reconstruction.
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| 6. |
- Lu, Yang, et al.
(författare)
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Precise tuning of interlayer electronic coupling in layered conductive metal-organic frameworks
- 2022
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Ingår i: Nature Communications. - : Nature Portfolio. - 2041-1723. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- Layered metal-organic frameworks attract interests for optoelectronics and spintronics. Here, the authors report a strategy to tune interlayer charge transport and thermoelectric properties via side-chain induced control of the layer spacing. Two-dimensional conjugated metal-organic frameworks (2D c-MOFs) have attracted increasing interests for (opto)-electronics and spintronics. They generally consist of van der Waals stacked layers and exhibit layer-depended electronic properties. While considerable efforts have been made to regulate the charge transport within a layer, precise control of electronic coupling between layers has not yet been achieved. Herein, we report a strategy to precisely tune interlayer charge transport in 2D c-MOFs via side-chain induced control of the layer spacing. We design hexaiminotriindole ligands allowing programmed functionalization with tailored alkyl chains (HATI_CX, X = 1,3,4; X refers to the carbon numbers of the alkyl chains) for the synthesis of semiconducting Ni-3(HATI_CX)(2). The layer spacing of these MOFs can be precisely varied from 3.40 to 3.70 angstrom, leading to widened band gap, suppressed carrier mobilities, and significant improvement of the Seebeck coefficient. With this demonstration, we further achieve a record-high thermoelectric power factor of 68 +/- 3 nW m(-1) K-2 in Ni-3(HATI_C3)(2), superior to the reported holes-dominated MOFs.
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| 7. |
- Lu, Yang, et al.
(författare)
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sp-Carbon Incorporated Conductive Metal-Organic Framework as Photocathode for Photoelectrochemical Hydrogen Generation
- 2022
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Ingår i: Angewandte Chemie International Edition. - : Wiley. - 1433-7851 .- 1521-3773. ; 61:39
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Tidskriftsartikel (refereegranskat)abstract
- Metal-organic frameworks (MOFs) have attracted increasing interest for broad applications in catalysis and gas separation due to their high porosity. However, the insulating feature and the limited active sites hindered MOFs as photocathode active materials for application in photoelectrocatalytic hydrogen generation. Herein, we develop a layered conductive two-dimensional conjugated MOF (2D c-MOF) comprising sp-carbon active sites based on arylene-ethynylene macrocycle ligand via CuO4 linking, named as Cu3HHAE2. This sp-carbon 2D c-MOF displays apparent semiconducting behavior and broad light absorption till the near-infrared band (1600 nm). Due to the abundant acetylene units, the Cu3HHAE2 could act as the first case of MOF photocathode for photoelectrochemical (PEC) hydrogen generation and presents a record hydrogen-evolution photocurrent density of ≈260 μA cm−2 at 0 V vs. reversible hydrogen electrode among the structurally-defined cocatalyst-free organic photocathodes.
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| 8. |
- Sher, Omer, et al.
(författare)
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Analysis of molecular ligand functionalization process in nano-molecular electronic devices containing densely packed nano-particle functionalization shells
- 2022
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Ingår i: Nanotechnology. - : IOP Publishing. - 0957-4484 .- 1361-6528. ; 33:25
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Tidskriftsartikel (refereegranskat)abstract
- Molecular electronic devices based on few and single-molecules have the advantage that the electronic signature of the device is directly dependent on the electronic structure of the molecules as well as of the electrode-molecule junction. In this work, we use a two-step approach to synthesise functionalized nanomolecular electronic devices (nanoMoED). In first step we apply an organic solvent-based gold nanoparticle (AuNP) synthesis method to form either a 1-dodecanethiol or a mixed 1-dodecanethiol/omega-tetraphenyl ether substituted 1-dodecanethiol ligand shell. The functionalization of these AuNPs is tuned in a second step by a ligand functionalization process where biphenyldithiol (BPDT) molecules are introduced as bridging ligands into the shell of the AuNPs. From subsequent structural analysis and electrical measurements, we could observe a successful molecular functionalization in nanoMoED devices as well as we could deduce that differences in electrical properties between two different device types are related to the differences in the molecular functionalization process for the two different AuNPs synthesized in first step. The same devices yielded successful NO2 gas sensing. This opens the pathway for a simplified synthesis/fabrication of molecular electronic devices with application potential.
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| 9. |
- Zhou, Guanqun, et al.
(författare)
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Two-stage reflective self-seeding scheme for high-repetition-rate X-ray free-electron lasers
- 2021
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Ingår i: Journal of Synchrotron Radiation. - 0909-0495. ; 28, s. 44-51
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Tidskriftsartikel (refereegranskat)abstract
- X-ray free-electron lasers (XFELs) open a new era of X-ray based research by generating extremely intense X-ray flashes. To further improve the spectrum brightness, a self-seeding FEL scheme has been developed and demonstrated experimentally. As the next step, new-generation FELs with high repetition rates are being designed, built and commissioned around the world. A high repetition rate would significantly speed up the scientific research; however, alongside this improvement comes new challenges surrounding thermal management of the self-seeding monochromator. In this paper, a new configuration for self-seeding FELs is proposed, operated under a high repetition rate which can strongly suppress the thermal effects on the monochromator and provides a narrow-bandwidth FEL pulse. Three-dimension time-dependent simulations have been performed to demonstrate this idea. With this proposed configuration, high-repetition-rate XFEL facilities are able to generate narrow-bandwidth X-ray pulses without obvious thermal concern on the monochromators.
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