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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