The mass spectrometry analysis of oxygenated volatile organic compounds (OVOCs) remains challenging due to their limited ionization efficiencies. In this study, we surprisingly found that, under vacuum-UV (VUV) excitation, a gaseous mixture of CHCl/HO/analyte (OVOCs) in N buffer generated large amounts of HO and protonated analyte even when the photon energy was lower than the ionization energy of the neutral species involved. In contrast to those obtained with VUV photoionization alone, the signal intensities of oxygenated organics can be amplified by more than 3 orders of magnitude. The isotope tracing experiment revealed that the proton donor is water, and the dependence of the signal intensities on the VUV photon intensities verified that the reaction was a single-photon process. The observed ionization process is assigned as an undocumented chemi-ionization reaction in which a complex formed from the ion-pair state CHCl*, HO, and analyte and then autoionized to produce the protonated analyte with the aid of the reorganization energy released from the formation of CHO and HCl. Essentially, here we present an efficient chemi-ionization method for the direct protonation of oxygenated organics. By the method, the mass spectrometric sensitivities toward acetic acid, ethanol, aldehyde, diethyl ether, and acetone were determined to be 224 ± 17, 245 ± 5, 477 ± 14, 679 ± 11, and 684 ± 6 counts pptv, respectively, in 10 s acquisition time. In addition, the present ionization process provides a new method for the generation of a high-intensity HO source (∼10 ions s, measured by ion current) by which general organics can be indirectly protonated via a conventional proton-transfer reaction. These results open new aspects of chemi-ionization reactions and offer new technological applications that have the potential to greatly improve mass spectrometry sensitivity for detecting trace gaseous organics.

All-inorganic perovskite CsPbBr3 has attracted intense attentions due to its inspiring optoelectronic properties and excellent stability. Growing large-size single crystals with high quality is vital both for the intrinsic property investigation and the high-performance device fabrication. Here, large-size CsPbBr3 single crystals (ϕ 30 mm × 100 mm) were grown by the modified Bridgman method. The surface morphologies of the as-grown CsPbBr3 single-crystal wafers were characterized by SEM, and inclusions with size of 1–2 μm were observed in the first-time grown crystal (labeled as CPB-1). By adopting a slower growth rate (0.2 mm/h) and cooling rate (5 °C/h) than that of CPB-1, the inclusions were eliminated in subsequent growth (labeled as CPB-2). The hole mobility-lifetime products were measured to be 3.92 × 10–3 and 1.46 × 10–2 cm2·V–1 for CPB-1 and CPB-2, respectively. The carrier mobility of CPB-2 was enhanced 1 order of magnitude from 10.1 ± 0.3 cm2·V–1·s–1 (CPB-1) to 101.3 ± 4.2 cm2·V–1·s–1 due to the elimination of inclusions. In addition, CPB-2 exhibited excellent α particles detection ability with the optimal energy resolution of 15.1% at −60 V bias. We provide an effective way to enhance the optoelectronic properties and device performance of melt-grown CsPbBr3 single crystal by preventing the formation of the inclusions.

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2D transitional metal dichalcogenide (2D-TMDC) materials, as inorganic graphene analogs (IGAs), have been intensively investigated for their novel chemical and physical properties when the thickness is reduced to a few atomic layers, such as MoS 2 , WS 2 , among others. [1] Tantalum disulfide, TaS 2 , one of the TMDC materials, has attracted growing attention recently. In the bulk state, TaS 2 occupies 2H or 1T structure, which is composed of covalently bonded STaS layers. 1T-TaS 2 with Ta in octahedral coordination with S atoms exhibits semiconducting behavior, and it has a commensurate charge density wave (CCDW) phase under 180 K. Adjusted by pressure, the superconductivity of 1T-TaS 2 develops in the CCDW state and survives to very high pressure. [2][3][4] 2H-TaS 2 with Ta in trigonal prismatic coordination with S atoms exhibits metallic behaviors with CDW phase transition (T CDW = 75 K) and superconductivity (T c = 0.8 K). [5][6][7][8] The electrical conductivity of single-crystal 2H-TaS 2 can reach 6.8 × 10 4 S m −1 at room temperature. [9] When the thickness is reduced to a few layers, interesting phenomena have been found, such as gate-tunable phase transition [10] and enhanced superconductivity, [11] which are promising properties for applications like electrical oscillators, [12] fast memories, [13] hydrogen evolution catalyst. [14] Until now, 2D TaS 2 has been mainly synthesized by the mechanical exfoliation method, [15] which is time consuming and of poor reproductivity and low yield. It has been noticed that the exfoliation of TaS 2 seems rather difficult and the atomically thin layers are unstable in ambient environments due to easy oxidation. [16] Complex encapsulation techniques are therefore required to help preserve the samples in air. [16] The chemical vapor deposition method [17] proves to be swift and effective in fabrication of high-quality 2D materials, but large-area synthesis of full-coverage atomically thin material is still in progress. For device applications, solution-based chemical synthesis is particularly important, as the product can be easily integrated into electronic devices.There is a new solution-based strategy to synthesize 2D materials in the form of inorganic/organic superlattice, in which the inorganic layers may get close to the low-dimensional state due to the spatial separation by the organic molecules. In our previous papers, we synthesized a hybrid superlattice with alternating 2D [TiS 2 ] monolayers and organic cations through an electrochemical reaction process. [18] The isolation of the [TiS 2 ] TaS 2 nanolayers with reduced dimensionality show interesting physics, such as a gate-tunable phase transition and enhanced superconductivity, among others. Here, a solution-based strategy to fabricate a large-area foil of hybrid TaS 2 /organic superlattice, where [TaS 2 ] monolayers and organic molecules alternatively stack in atomic scale, is proposed. The [TaS 2 ] layers are spatially isolated with remarkably weakened interlayer bonding, resulting in lattice vibration ...

A compact high temperature sensor utilizing a multipath Michelson interferometer (MI) structure based on weak coupling multicore fiber (MCF) is proposed and experimentally demonstrated. The device is fabricated by program-controlled tapering the spliced region between single mode fiber (SMF) and a segment of MCF. After that, a spherical reflective structure is formed by arc-fusion splicing the end face of MCF. Theoretical analysis has been implemented for this specific multipath MI structure; beam propagation method based simulation and corresponding experiments were performed to investigate the effect of taper and spherical end face on system's performance. Benefiting from the multipath interferences and heterogeneous structure between the center core and surrounding cores of the all-solid MCF, an enhanced temperature sensitivity of 165 pm/°C up to 900°C and a high-quality interference spectrum with 25 dB fringe visibility were achieved.

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Light-emitting field-effect transistors (LEFETs) have attained great attention due to their special characteristics of both the switching capacity and the electroluminescence capacity. However, high-performance LEFETs with high mobility, high brightness, and high efficiency have not been realized due to the difficulty in developing high electron and hole mobility materials with suitable band structures. In this paper, quantum dot hybrid LEFETs (QD-HLEFETs) combining high-luminous-efficiency quantum dots (QDs) and a solution-processed scandium-incorporated indium oxide (Sc:InO) semiconductor were demonstrated. The red QD-HLEFET showed high electrical and optical performance with an electron mobility of 0.8 cm V s, a maximum brightness of 13 400 cd/m, and a maximum external quantum efficiency of 8.7%. The high performance of the QD-HLEFET is attributed to the good energy band matching between Sc:InO and QDs and the balanced hole and electron injection (less exciton nonradiative recombination). In addition, incorporation of Sc into InO can suppress the oxygen vacancy and free carrier generation and brings about excellent current and optical modulation (the on/off current ratio is 10 and the on/off brightness ratio is 10).

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